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Orthodox vs Catholic: How the Two Traditions Differ

Orthodox vs Catholic

Until the year 1054, the Christian Church in the West (Rome) and the Christian Church in the East (Constantinople, Alexandria, Antioch, Jerusalem) were one body. The mutual excommunications of that year began a long separation that hardened into two distinct traditions, the Roman Catholic Church and the Orthodox Church. We share more than divides us, but the differences are real and worth understanding clearly.

This page is offered as a calm explanation, not a polemic. Orthodox Christians and Catholics are not enemies. We are estranged family, and our prayer is that the family is one day fully reconciled.

What we share

  • The Holy Scriptures (Old and New Testaments)
  • The Nicene Creed
  • The seven Holy Mysteries, also called sacraments
  • The veneration of the Mother of God (Theotokos) and the saints
  • The apostolic succession of bishops
  • A liturgical, sacramental, hierarchical understanding of the Church
  • The honor of the holy fathers of the first millennium

Where we differ

1. The role of the Pope of Rome

Catholic teaching holds that the Pope, as the Bishop of Rome, has universal jurisdiction over the whole Church and that when he speaks officially on matters of faith and morals, he is preserved from error (papal infallibility).

Orthodox teaching holds that the Bishop of Rome was historically the first among equals, a place of honor among the five ancient patriarchs (Rome, Constantinople, Alexandria, Antioch, Jerusalem), but never with jurisdiction or infallibility over the whole Church. Truth is preserved by the consensus of the bishops and the faithful together, expressed through ecumenical councils and the lived tradition of the Church.

2. The Filioque

The original Nicene Creed states that the Holy Spirit “proceeds from the Father.” The Western Church later added “and the Son” (in Latin, “Filioque”), so that the Western version reads “proceeds from the Father and the Son.”

Orthodox Christians do not add Filioque. The reasons are both historical (the addition was made without an ecumenical council) and theological (Orthodox theology teaches the Father is the single source of the Holy Spirit; Filioque can obscure that). The phrase is small, but the meaning is not.

3. Purgatory

Catholic teaching includes Purgatory as an intermediate state of purification after death for those bound for heaven.

Orthodox teaching prays for the departed and trusts in God’s mercy, but does not teach Purgatory as a distinct intermediate state. We hold that the soul after death awaits the general resurrection and the final judgment, and that our prayers continue to assist the departed.

4. The Immaculate Conception

Catholic teaching defines that the Virgin Mary was conceived free from original sin.

Orthodox teaching honors the Theotokos as the most blessed of all women, the Mother of God, but does not hold the Immaculate Conception as a doctrine. We teach that Mary was preserved by grace throughout her life and made worthy to bear the Son of God, but we do not separate her from the rest of humanity at the moment of conception.

5. Worship style

Orthodox Divine Liturgy has remained substantially unchanged since the 4th century. We sing nearly the entire service, we venerate icons, we cross ourselves frequently, we stand for most of the service, and we receive Communion from a common spoon. Latin Rite Catholic Mass (the most familiar form) has undergone significant reform, most recently after the Second Vatican Council in the 1960s.

A Ukrainian Catholic Mass (Byzantine Rite) actually looks very similar to Orthodox Divine Liturgy. See our separate page Orthodox vs Ukrainian Catholic for that comparison.

6. Married clergy

Orthodox priests may be married, provided they were married before ordination. Bishops are chosen from among the celibate (typically monastic) clergy.

Roman Catholic priests of the Latin Rite are required to be celibate. Eastern Catholic churches in communion with Rome (including the Ukrainian Catholic Church) do allow married priests.

7. Calendar

Orthodox churches use either the Julian Calendar (Russian, Serbian, some others) or the Revised Julian Calendar (Ukrainian, Greek, Antiochian, most others). St. Michael Ukrainian Orthodox Church follows the New Calendar (Revised Julian), so our Christmas is December 25 and our fixed feasts align with the Western calendar. Pascha (Easter) is calculated by a different formula from Western Easter, so the date often differs.

Catholics use the Gregorian Calendar uniformly.

Can a Catholic attend Orthodox Liturgy?

Yes. Catholic visitors are welcome at our Divine Liturgy and welcome to receive the antidoron (blessed bread) at the end of the service. However, by Orthodox practice, Holy Communion is given only to Orthodox Christians who have prepared (confession, fasting). This is not unkindness; it expresses our belief that Communion is the sign of full unity in faith.

The same rule applies in reverse: Orthodox Christians do not receive Communion in Catholic churches.

Can an Orthodox Christian marry a Catholic?

Yes, with a bishop’s blessing. The marriage takes place in the Orthodox Church, the Catholic spouse is asked to commit to raising children Orthodox, and the wedding follows the Orthodox form. See Orthodox Wedding for the full process.

Can a Catholic become Orthodox?

Yes. Most baptized Catholics are received into the Orthodox Church through Chrismation rather than re-baptism, because Catholic Trinitarian baptism is recognized. The process typically includes a period of catechesis with the priest. See Becoming Orthodox and The Catechumen Journey for details.

Frequently Asked Questions

Are Orthodox and Catholic the same? No. We share most of the early Christian inheritance, but on the points above we have understood and lived the faith differently for almost 1,000 years.

Which one is the “true” church? Orthodox Christians believe the Orthodox Church preserves the faith of the apostles and the early Church without addition or alteration. Roman Catholics believe the same about their own tradition. The answer to this question depends on whose criteria you use to judge.

Is the Pope a heretic? No, and Orthodox Christians should be careful not to speak that way. We disagree with Catholic claims about papal jurisdiction and infallibility, but the Pope is a Christian leader of a long tradition. Disagreement is not contempt.

Are Orthodox and Catholic working toward unity? There are ongoing theological dialogues. Real unity will require resolving the points above, which has not happened in 1,000 years and will likely take more time. We pray for it.

Learn More

If you have questions, please reach out. Fr. Stephen Siniari is glad to speak with anyone seeking to understand the Orthodox faith, whether you are Catholic, another Christian tradition, or no tradition at all.

St. Michael Ukrainian Orthodox Church 9201 60th St, Pinellas Park, FL 33782 Phone: 727-777-4450