Orthodoxy vs. Catholicism – How Are They Similar and Different?

Differences between the Orthodox and Catholic Churches

Sadly, divisions within churches have occurred throughout history. However, one schism – called the Great Schism – was perhaps the most tragic for the Christian Church. After almost a thousand years after it happened, there is still no reason to believe it will be healed any time soon. In this article, we review the similarities and differences between the Orthodox and Catholic Churches.

When and why did Christianity split into Orthodoxy and Catholicism?

The Great Schism occurred in 1054, although disagreements between the eastern and western parts of the Church had existed before. The Great Schism was far from the first division between the churches: Photius’ controversy is an example of an earlier schism. 

The division of the Church into two parts happened because each part was going its way, even though they remained united for some time. The West and East had different rites and had distinct theological and liturgical traditions. The Eastern and Western churches gave divergent answers to questions of worship, which sometimes created conflicts. Sadly, it was not always possible for both Churches to remain in dialogue due to great distances and the difficulties of travel. Letters could take months or years to reach their addressees. 

Naturally, these circumstances were highly conducive to divisions. The narrative below may seem an over-simplification, but a detailed exploration of the causes of the schism would take volumes of text.

What is Orthodoxy

Orthodoxy has come to refer to the faith of the eastern part of the Single Church, although the term itself was introduced in the second century AD. The Orthodox are most concerned with the preservation of the purity of the apostolic faith, which is what the term means. “Orthodoxia” translates from Greek as “true worship”.

What is Catholicism

Catholicism refers to the Western Christian Church. The term “Catholic” is also ancient and was first used in the epistle to the Smyrnans by St Ignatius the God-Bearer. It means “universal” or “ecumenical” and is used in the Niceno-Constantinopolitan Creed: “Εἰς μίαν, ἁγίαν, καθολικὴν καὶ ἀποστολικὴν Ἐκλησίαν” – “I believe in one Holy, Catholic and Apostolic Church”. Catholic teachings emphasise some teachings of the Holy Fathers over others and treat as dogmas the ideas and concepts that receive controversial interpretations in the Church Tradition.

Main similarities and differences between Orthodoxy and Catholicism

Basis for comparison




Both Churches are part of the once united, Universal Church founded by the Lord Jesus Christ Himself.


Administrative structure

The head of the Church is Jesus Christ. The Church is divided into several independent patriarchates and independent or autocephalous churches. The supreme organ of church government is the Council. 

The head of the Church is the Roman Pope, the Vicar of Christ on earth. For Catholics, the pope is an exceptional figure, possessing infallibility in matters of doctrine. Decisions of a church council are valid only after approval by the Pope. 


There is a three-level hierarchy of the clergy: deacon, presbyter and bishop.



Depending on the decision of each local Church the Julian, New Julian or Gregorian calendars are used. 

The Gregorian calendar is used.

Biblical canon

Both Churches share the same New Testament Canon (4 Gospels, 14 Epistles of st. apostle Paul, 7 Ecumenical Epistles, the book of Acts, the book of Revelation). 

Orthodox and Catholic Old Testament canon includes 39 books.

There are also 11 non-canonical books: Tobias, Judith, Wisdom of Solomon, Sirach, Baruch, 1 Maccabees, 2 Maccabees, 3 Maccabees, 2 Esdras, 3 Esdras, the Letter of Jeremiah. Although these books are not part of the canon, they are considered edifying.

There are 7 deuterocanonical (greek ‘deuteros’ means ‘second’) books in the Catholic Biblical canon: Tobias, Judith, 1 Maccabees, 2 Maccabees, Wisdom of Solomon, Sirach and Baruch. There are also additions to books of Esther and Daniel that are deuterocanonical. 

Rites, customs, practices


Worship rite

The Byzantine rite is the most common. Some churches in Europe and America practice the Latin rite, and even more rarely the Gallican rite. The Latin and Byzantine rites are both viewed as equally salvific in the Orthodox and the Catholic Churches.

The Roman Catholic Church keeps to the Latin rite. Local Catholic churches, also called Eastern Catholic churches, may use the Eastern rites (Byzantine, Syriac, etc.). Such churches keep the rite and canon law but are fully subordinate to Rome.


Icons are venerated in both Churches but understand the meaning and significance of icons somewhat differently.

Orthodox icons mainly depict the image of a saint in heavenly glory, that is, free from the imperfections of earthly life.

Catholic icons underline the sensuous and/or realistic representation of a saint or event.  Most Catholic churches have noticeably fewer icons than the average Orthodox church. In addition to icons, statues are widely venerated by Catholics, an uncommon practice among the Orthodox.


One-day fasting is on Wednesdays and Fridays, except for great feasts. Four fasting periods: Christmas, Great Lent, St. Peter’s and Dormition. In terms of diet, fasting means avoiding meat, eggs, dairy products and fish. on certain days.

Fasting is practised one day a week, on Fridays, except on great feasts.  There are two fasting periods: the Christmas fast and the Lenten fast.  In food, fasting means avoidance of meat.

Celibacy rule for the clergy

A candidate for the clergy may choose whether to marry or to remain celibate.  Deacons and priests may marry, but a bishop must be celibate. The dissolution of a marriage is not acceptable for a clergyman.

Celibacy is a strict rule for all priests except deacons.  Eastern Catholic local churches may have other rules of celibacy according to their canonical law.


Monastic life is based on the Tipikon, a statute which regulates its liturgical and monastic aspects. Nevertheless, each monastery has particularities and customs of its own.

There are more than fifty monastic orders. Each has its charter, which brings considerable diversity to Catholic monasticism. 

Veneration of the saints

Catholics and Orthodox both venerate the saints glorified before the Great Schism. After the Schism, only saints belonging to the Orthodox Church are venerated.

Some saints who belonged to the Orthodox Church after the schism are also venerated.


Many feasts are common to both faiths. For example, Christmas, Easter, Ascension, etc. Some feasts are celebrated only by the Orthodox, e.g. the Protection of the Theotokos (in the Russian Church) and The Origin of the Precious Wood honest and life-giving Cross of the Lord.

Some feasts are celebrated by Catholics only. Examples: the Immaculate Heart of the Blessed Virgin Mary, the Heart of Christ, and the Body and Blood of Christ.

Ecumenical Councils

Seven Ecumenical Councils are recognized: Nicaea in 325, Constantinople in 381, Ephesus in 431, Chalcedon in 451, II in 680 and II Nicaea in 787. No Ecumenical Council could be possible before the restoration of the unity of the Church.

In addition to the seven Councils recognised by the Orthodox, there are fourteen more (twenty-one Ecumenical Councils in total). The last Ecumenical Council took place from 1962 to 1965 and was called the Second Vatican Council.

Attributes of God

For the most part, Catholics and Orthodox share the same ideas of God. God is unique, immutable, eternal, omnipresent, wise, omniscient, holy, true and loving Creator and Sustainer of the universe.


Manifestations of God’s actions in  the world

The dogma of the Most Holy Trinity is confessed, and similarly the divinity of Christ. The action of God in the world is seen as the manifestation of divine energy. The Divine energy is indivisible and of one essence with God. In other words, God Himself is present in the world and connects the human being to God through His energies.

No doctrine of divine energies is preached. God’s actions in the world are creations and are separate from God. 

Views on the proceeding of the Holy Spirit 

The descent of the Holy Spirit from the Father is confessed.

Even before the Great Schism, the Council of Toledo in 681 amended the Creed of the Western Church, according to which the Holy Spirit proceeds from both the Father and the Son. This doctrine was subsequently enshrined only in the Catholic Church, while the Orthodox Church condemned it as heresy.   This doctrine was called the “filioque”, which is Latin for “and of the Son”. The filioque was originally adopted to combat Arianism.

Teachings on the Theotokos

The Mother of God is widely venerated in both Churches. Her exceptional holiness, the Virginity of God, is recognized.


Immaculate conception of the Theotokos

Mary was undoubtedly God’s holy Chosen, but still an ordinary person in terms of human nature.

The Virgin Mary herself was conceived immaculately, free from the consequences of original sin, and sinless.

Ascension of the Theotokos

The doctrine that the Virgin Mary’s body was taken to heaven after her Assumption has some substance in Tradition. Nevertheless, it cannot be asserted unequivocally. 

The doctrine of the Ascension of the Virgin Mary was proclaimed as dogma in 1950.

Sacraments of the Church


Who performs the sacraments?

Both Churches recognise the seven Sacraments, and acknowledge that a canonical clergyman must administer the Sacraments; they also proclaim the presence of a visible sign of their administration (the substance of the Sacrament) and the requirement of faith on the part of the recipient of the Sacrament. God is the One who performs the sacrament.

The sacrament is performed by God, but the priest acts in persona Christi – in the person of Christ. That is, God acts directly through the hands of the priest.


The baptismal formula is used: “The servant of God is baptised…”.

The baptismal formula used is “I baptise you…”.


Is performed immediately after Baptism.

It is called Confirmation. It is performed only after the baptised person has reached the age of fourteen.


For the Holy Sacrament to be valid, a penitent attitude must be present.

Repentance is not an absolute requirement for a valid confession. It is sufficient for the penitent to have remorse. 


Leavened bread is used.

During Communion, the Body and Blood of Christ are offered to everyone.

Unleavened bread is used.  Only the priest takes communion of the body and blood. The laity only receive Communion with the Body.


Direct participation of the wedded couple in the order of the sacrament is required. The priest blesses the couple, joins their hands and puts the rings on the fingers of the newlyweds. Dissolution of a marriage is possible. 

The declaration of the wish of the man and a woman to marry is sufficient for a marriage to be considered ecclesiastical and consecrated. Although there is also a direct ecclesiastical ordinance of marriage.  As a matter of principle, marriages cannot be dissolved. However, a dispensation is possible, i.e. a declaration of a marriage to be null and void.


In both Churches, apostolic succession is maintained, which is considered the foundation of the priesthood.

There is a separate rank of cardinals – the highest rank of the clergy after the pope, who belonged, de-facto – to every degree of the priesthood.  Before 1917, even laymen could be ordained cardinals, but after 1917 this possibility was reserved only for priests or bishops.  From 1962, cardinals could be selected only from bishops, and only with the blessing of the pope, from priests.

Extreme Unction

It is performed on the sick. The oil may be consecrated by a presbyter or a bishop.

Performed only on a dying person. The oil can only be consecrated by a bishop.

Validity of the sacraments of the other church

The sacraments are recognized as valid in both Churches, with some conditions.  By oikonomia, when converting from Catholicism to Orthodoxy, Baptism, Anointing, Marriage, and Ordination are not repeated. The Orthodox may not participate in the sacraments of the Catholics. 

The sacraments of the Orthodox are fully recognised by Catholics.  On conversion from Orthodoxy to Catholicism, the Sacraments of Baptism, Anointing, Marriage and Ordination are not administered again.  According to Canon 844 of the Code of Canon Law, Catholics are allowed to participate in the Sacraments of Penance, Communion and Holy Communion with the Orthodox in the absence of a Catholic church or for “genuine spiritual benefit.   Where the Orthodox wish to participate in such Sacraments with Catholics, they must have permission to do so from a Catholic priest. 

Teachings on the afterlife

After death, the soul is believed to undergo a succession of trials set up by demons to prevent it from reaching the Throne of God. Nevertheless, the doctrine of posthumous ordeals is preached as a dogma.

It is preached as dogma that the souls of deceased believers in need of purification from sins go through a purgatory – before they are united with God.



Thankfully, both Churches can still agree on most of the fundamental tenets of each other’s doctrine. Nevertheless, considerable differences remain, that is theological, and also historical and cultural. 

Some of the most persistent disagreements are as follows:

— The Catholic doctrine of the Filioque, which, in the Orthodox opinion, undermines the Father’s role in the Holy Trinity by proclaiming the Son equal to the Father. The Orthodox believe that such a view contradicts the Holy Scripture and the Church Tradition.

— Recognition of papal supremacy, i.e. the teaching that the Pope, as the physical head of the Church, has immediate, supreme, universal jurisdiction over every Christian. The Orthodox underline that before the Great Schism, the pope was first among equals in the pentarchy, but lost this dignity when the doctrine of the absolute supremacy of the Roman High Priest was accepted (cf. Mt 23:12).

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  1. This is very helpful, and it is good to see a factual approach, free from the harsh words that sometimes accompany discussions of this subject. One question I have – would it be possible to add a section, about differences between which books of the Old Testament the two churches accept? Thank you

    1. Thank you! I completely agree on the fact that there’s too much hate on this subject. It feels like the point of the most controversies going on is just to prove that the other side is wrong and not to search for ways of achieving unity once again. Sorta makes me sad.

      I knew I’ve missed something! Thank you, I’ve just updated the article with “Biblical canon” section.

  2. Hello. This is a great article. I am Orthodox. There must be added something very important. There is a tendency since the first half of the 20th century started by some modernistic Orthodox theologians who rejected the penal substitutionary atonement in its legal aspect as a supposedly non-Orthodox teaching and a supposedly Western innovation invented by Anselm of Canterbury in the 11th century.

    It is not an Orthodox but a 20th century Orthodox modernistic view that by dying instead of us Christ did not satisfy God’s justice on the Cross. The modernistic position is that He saved us from death (which is true) by dying instead of us but modernism denies that by dying instead of us on the Cross He also payed the debts for our sins, appeased God’s wrath (which is not a passion but refers to His justice) and thus saved us also from the second death which is the eternal punishment for the unrepented sinners which we would undergo had He not incarnated and dyed for us and instead of us. The penal substitutionary atonement in the second aspect of salvation from the second death, is denied by modernists. Modernism rejects the legalistic view of any sin as a lawlessness that requires a punishment in case the sinner does not repent but considers sin to be only an illness. That is why modernism denies that by dying instead of us on the Cross Christ saved also from the eternal punishment for unrepented sins.

    Modernists accept that the main aim of His Incarnation is restoring the union of man with God through theosis which is true. But by denying our justification by Christ on the Cross in the sense of paying the debts for our sins and doing a legal acquittal of sinners by satisfying God’s justice, modernism separates the legal aspect of justification by Christ’s Sacrifice as the reason (John 7:37-39) for the sanctification and theosis (the deification of by grace) of the believers, from theosis. Instead modernism claims that the aim of Christ’s Incarnation is only theosis.

    As modernism rejects the eternal punishment for the unrepented sinners after the Last Judgment but claims that both the righteous ones and the unrepented sinners will be in the presence of God but will experience His presence and love in different ways – the righteous ones as blessing and the wicked as fire (so modernism rejects the physical suffering in a physical fire which is also an un-Orthodox understanding).

    The legalistic view of original sin which is expressed most thoroughly by St.Augustine but not only by him, is denied by modernists for it legal approach. If we go through the history of the Orthodox polemics with the West regarding the differences between East and West, in the period between the 11th and the 19th century, we will see nowhere a rejection by the Orthodox theologians of the western legalistic understanding of the original sin and the legal aspect of the penal subsitutionary atonement as supposedly Western inventions. If the western understanding of the original sin and the penal substitutionary atonement in the legal aspect, were Western innovations, they would have been condemned as such exactly in the polemics of the Orthodox with the West, for example during the attempts for a union between Rome and the Eastern Orthodox Church because during those attempts there clearly arose the dogmatic differences between the East and the West. But during those attempts there is no case of such condemnation. The legalistic view of the original sin and the Redemption in the form of the legal understanding of the penal substitutionary atonement, is an Orthodox teaching. Unfortunately anti-legalism has become very popular among Orthodox people in the recent decades.

    A more recent example of anti-legalism can be seen in the Letter sent to Pope Francis on April 10, 2014 by His Eminence, the Metropolitan of Piraeus, Seraphim, and His Eminence, the Metropolitan of Dryinoupolis, Andrew, both of the Church of Greece, on page 5 mentions among the real differences between Rome and Orthodoxy also the following non-existing difference:,,… The fact that Papism is a heresy is revealed by the appalling false doctrines which you confess. These are: …XXIII) the doctrine of the satisfaction of divine justice (the result of confusion regarding original sin and the legalism which is prevalent in Papism);…“.

    1. Hello, I am very grateful for your reply. It is a much-needed addition in case someone would like to go deeper in the subject. I personally focused on giving a basic overview on this matter. But I can’t deny there are still too many notable things that part orthodoxy and catholicism e.g. reservatio mentalis. Thank you again!

  3. Thank you for the response. You have perfectly expressed the true differences. I have no remark on that. I was just pointing to a non-existing difference, a straw man – the claim that the penal subsitutionary atonement in its legal understanding is not an Orthodox teaching. That claim is a straw man that was invented by modernistic theology in the 20th century but unfortunately that straw man has become very popular and is thought by many Orthodox people nowadays to be something that the Orthodox Church supposedly teaches while in fact it does not teach it but modernistic theology claims that it teaches it.

    One of the modernistic arguments for the rejection of the penal substitutionary atonement is the claim that the penal substitution leads to a split in the Most Holy Trinity. But that the penal substitution does not cause a split because the Sacrifice is offered to the Three Persons of the Holy Trinity, is an Orthodox teaching. Also that that God was offended when Adam sinned and God had to be satisfied for the offence which happened with the Sacrifice, is an Orthodox teaching. Both teachings are clearly expressed in the Tomos of the Council of Constantinople from 1157 where it is said:

    “By selecting a few of the many testimonies of the divine Fathers as a clear proof of the truth, we have placed this in the present list, avoiding the scope of speech. Those who wish to be diligent should draw the definition of this dogma, drawing on many other testimonies. Since the divine Fathers have spoken unanimously that the Lord Christ voluntarily sacrificed Himself by offering Himself according to His humanity, and accepted the sacrifice as God, together with the Father and the Spirit, on this ground on which we have been united before, it is appropriate for the pupils of the Church to think (about this matter), being worshipers of the Trinity. The God-man Word during the Lord’s Sufferings, brought the Salvific Sacrifice to the Father, to Himself and to the Spirit, from Whom (plural – the Three Persons) man was summoned from nothingness to being, Whom (pl.) he offended, violating the commandment, and with Whom (pl.) the reconciliation was made through the sufferings of Christ. …‘‘

    Again, thank you for the response and keep up the good work!

  4. Nice work! However, as a Catholic, I need to offer some corrections from “the other side.” Please understand that I’m only offering these to clarify, not to criticize. I’d love to find more places with common ground!

    Administrative Structure: Jesus Christ is the head of the Church. The Church can be roughly divided into the Church Militant (or Church on Earth), which is headed by the Pope as the Vicar of Christ; the Church Suffering (in Purgatory) and the Church Triumphant (in Heaven). The latter two are seen as being directly headed by Jesus Christ himself.

    Biblical Canon: In practical application, most Catholics do not differentiate between the deuterocanonical books and other canonical Old Testament books. They are all considered to be divinely inspired.

    Worship Rite: The Church isn’t considered to have a name, per se, since “Catholic” means universal; however most Catholics accept the term as a proper noun. While the Latin or Roman Rite is the largest of the rites, the Eastern Rites are considered co-equal to the Latin Rite. (The Latin Rite is the only extant Western Rite, but there have been other historical Western Rites.) All ultimately are responsible to the Pope. Although it hasn’t yet happened, it’s entirely possible that a future Pope could be elected from one of the Eastern Rites.

    Icons: Most saints, in both iconography and statuary, are represented with items that are reflective of the saint’s particular life. As an example, St. Benedict of Nursia is often depicted with a raven, due to a story about a raven saving his life by eating poisoned bread. St. Christopher is often depicted carrying the Christ Child. St. Mary of Magdala (St. Mary Magdalene) is often shown holding a red egg. Catholics often consider these items to be symbolic rather than realistic.

    Fasting: Catholics differentiate between abstinence from meat, which is the norm for most Fridays outside of Lent and Advent, and fasting, which is defined as one full meal per day. There is a mandatory fast on Good Friday and many Catholics fast on Fridays during Lent and Advent as well as on Ash Wednesday.

    Immaculate Conception: it’s important to emphasize here that Catholics believe that Mary was a mortal person. What we believe is that she received her salvation from Jesus prior to her conception, rather than after conception (and baptism, etc.) like every other mortal person. This is primarily because Mary is the Mother of God and God cannot come from even the slightest hint sin; therefore, Mary *had* to be perfectly sinless despite being mortal.

    Sacraments: Deacons may baptize, witness or perform marriages, and distribute (but not consecrate) the Eucharist. Deacons may also, in the absence of a priest, lead a prayer service that includes the distribution of the Eucharist. Most deacons are called to specific ministries of service within the parish, although they also assist at the altar.

    Anointment/Confirmation: this can be administered anytime after age seven (the age of reason). The actual age depends on local and/or national custom and ranges from seven to eighteen, with thirteen, fourteen and sixteen being the most common normative ages. Side note: children over the age of reason may not be baptized unless the child themself consents; in this case parental consent is not sufficient.

    Penitence: A contrite attitude absolutely required for a valid receipt of the Sacrament of Reconciliation. We distinguish between perfect contrition (sorrow for having offended God) and imperfect contrition (sorrow for having created a bad situation). The former is preferable, but the latter is sufficient, particularly if it helps the penitent move toward the former.

    Communion: the priest is required to take it under both species. While most laypersons take the body, lay receipt of the blood is dictated by local and national custom; in the U.S. prior to COVID, lay receipt of the blood was normative. Four methods of Eucharistic receipt are permissible: body in the hand, body on the tongue, blood via the chalice, or both via intinction (body placed on the tongue after being dipped in the blood). Receipt of either species is considered to be a complete Eucharist, that is, those with celiac disease can often simply receive the blood.

    Marriage: the Eastern Rites’ custom is for the priest to bless the couple and the priest is considered the minister of the Sacrament. In the Western Rites, while the husband and wife are the ministers of the Sacrament, there must be at least two witnesses, one of whom is a Catholic in good standing. As a matter of practical application, the latter is normatively either a priest or deacon.

    Extreme Unction: may be performed in the case of any grave illness, and is more properly called “Anointing of the Sick.” It is especially called for in the case of an inpatient hospitalization or before beginning a long course of treatment such as chemotherapy.

    Other Church’s Sacraments: As a matter of politeness and ecumenical relations, Catholics are usually advised not to receive Sacaments at an Orthodox parish unless specific permission is given by the Orthodox priest, even in cases where Catholic administration is not possible.

    1. Thank you, Catherine! Your clarification is really helpful.

      P.S. I was shocked when I learned that the article stated that Catholics do not believe that Our Lady was mortal. I write articles in Russian and then pass them on to translators. I don’t always have time to reread the translated articles, so sometimes bizarre mistakes slip through. I just fixed it. Thank you again

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