Catholic and Orthodox Christians share the same New Testament and nearly the same Old Testament — but not exactly. The Orthodox communions preserve a slightly larger Old Testament canon, reflecting their reliance on the ancient Septuagint translation. Here is precisely where they differ.
The canons side by side
| Book | Catholic | Greek Orthodox | Slavic Orthodox (Russian) |
|---|---|---|---|
| Tobit, Judith | Yes | Yes | Yes |
| 1 & 2 Maccabees | Yes | Yes | Yes |
| Wisdom, Sirach, Baruch | Yes | Yes | Yes |
| 1 Esdras (3 Esdras) | No | Yes | Usually no |
| 3 Maccabees | No | Yes | Usually no |
| Psalm 151 | No | Yes | Usually no |
| 4 Maccabees | No | In an appendix | In an appendix |
| 2 Esdras (4 Esdras) | No | In an appendix | In an appendix |
| Total books | 73 | 79 | ~77 |
Note: numbering varies by edition — "1 Esdras" in Orthodox Bibles corresponds to Ezra material arranged differently from Catholic editions.
Why the difference?
Both canons grew from the Septuagint, the 3rd–2nd century BC Greek translation of the Hebrew Bible used by Greek-speaking Jews and, later, by virtually all early Christians. But while the Western church gradually settled on a 73-book canon confirmed at Trent (1546), the Eastern churches never held a single council that defined one uniform canon. Regional traditions — Greek, Slavic, Georgian, Ethiopian — preserved slightly different sets.
The Ethiopian Orthodox Church holds the largest canon in Christianity (81 books, including Jubilees and 1 Enoch), a reminder that "the biblical canon" has never been one single global list.
Text, not just contents
The deeper difference is textual. The Orthodox Old Testament follows the Septuagint text — which sometimes differs from the Hebrew Masoretic text behind Catholic and Protestant translations. Famous cases: Psalm numbering differs by one in the Slavic tradition, and the Septuagint of Jeremiah is roughly one eighth shorter than the Hebrew text. The Orthodox also accept the Septuagint form of certain doctrinally weighty passages, such as Isaiah 7:14's "virgin".
What they share
- The identical 27-book New Testament
- The seven Deuterocanonical books (Tobit, Judith, Wisdom, Sirach, Baruch, 1 and 2 Maccabees) with additions to Esther and Daniel
- The conviction that the canon is a product of the church's reception, not a modern scholarly reconstruction
Read both canons
FourFaiths carries both: the Catholic Douay-Rheims (73 books) and an Orthodox edition with the books of the larger Eastern canon.