Timothy Ware, in his well-known book, The Orthodox Church (New York: Penguin Books, 1980 edition, 208-209), writes:
As its authoritative text for the Old Testament it [the Orthodox Church] uses the ancient Greek translation known as the Septuagint. When this differs from the original Hebrew (which happens quite often), Orthodox believe that the changes in the Septuagint were made under the inspiration of the Holy Spirit, and are to be accepted as part of God's continuing revelation . . .Likewise, Stanley S. Harakas, in The Orthodox Church: 455 Questions and Answers (Minneapolis: Light & Life Publishing Co., 1987, 27) writes:
The Hebrew version of the Old testament contains thirty-nine books. The Septuagint contains in addition ten further books, not present in Hebrew, which are known in the Orthodox Church as the 'Deuter-Canonical' books. These were declared by the Councils of Jassy (1642) and Jerusalem (1672) to be 'genuine parts of Scripture'; most Orthodox scholars at the present day, however, following the opinion of Athanasius and Jerome, consider that the Deutero-Canonical Books, although part of the Bible, stand on a lower footing than the rest of the Old Testament.
Roman Catholics accept seven of the Deuterocanonical Books. The Orthodox accept all 10.For a more in-depth treatment, see: The Old Testament in the Orthodox Church, by Fr. R. Stergiou (Greekl Orthodox). He summarizes:
Even though the different Traditions of Orthodoxy may differ in which books they include in the Old Testament Canon, the fact remains that the Conscience of the Church generally accepts the Septuagint (LXX) or Alexandrian Canon....
St. Athanasius is one of the favorites of Protestants (probably second to St. Augustine in that regard). It's true that he did seem to lower the status of the deuterocanonical books somewhat, but not to a sub-biblical level, as noted by my good friend Gary Michuta, in his excellent book, Why Catholic Bibles are Bigger (Port Huron, Michigan: Grotto Press, 2007, 110-112; footnote numbering my own):
Athanasius quotes both Baruch and Susanna right along passages from Isaiah, Psalms, Romans, and Hebrews; he makes no distinction or qualification between them . Wisdom also is used as an authentic portion of sacred Scripture . . .:The great Protestant Bible scholar F.F. Bruce confirms Michuta's analysis:
But of these and such like inventions of idolatrous madness, Scripture taught us beforehand long ago, when it said, 'The devising of idols, as the beginning of fornication, and the invention of them, the corruption of life . . .' [Ws 14:12] And later in the same work:
For since they were endeavouring to invest with what Scripture calls the incommunicable name . . . This reference to the "incommunicable name" comes from Wisdom 14:21 . . .
Athanasius quotes another passage from Wisdom as constituting the teachings of Christ, the Word of God. He undoubtedly uses it to confirm doctrine.  In another argument against Arians, he calls both the Protocanonical Proverbs and the Deuterocanonical Wisdom "holy Scripture" . . .  . . .
Athanasius also quotes the book of Sirach without distinction or qualification, in the midst of several other scriptural quotations.  . . . Athanasius calls the Book of Judith Scripture.  Tobit is cited right along with several Protocanonical quotations  , and even introduced with the solemn formula "it is written." 
 Four Discourses Against the Arians, Discourse 1.12.
 Against the Heathen, 11.1. Emphasis added.
 Against the Heathen, 1, 17.3.
 On the Incarnate Word, 4.6; 5.2.
 Defense Against Arius, 1, 3.
 Life of Anthony, 28 and Apology Against the Arians, 66.
 Four Discourses Against the Arians, Discourse 2.35 . . .
 Defense of Constantius, 17. Tobit is cited after Matthew and Isaiah.
 Defense Against Arius, Part 1, 11.
As Athanasius includes Baruch and the 'Letter of Jeremiah' in one book with Jeremiah and Lamentations [in his list of the OT canon], so he probably includes the Greek additions to Daniel in the canonical book of that name, and the additions to Esther in the book of that name which he recommends for reading in church [but doesn't list as a canonical book] . . .With St. Jerome, it was a different situation altogether. Michuta concedes:
In practice Athanasius appears to have paid little attention to the formal distinction between those books which he listed in the canon and those which were suitable for instruction of new Christians. He was familiar with the text of all, and quoted from them freely, often with the same introductory formula -- 'as it is written', 'as the scripture says', etc.
(The Canon of Scripture, Downers Grove, Illinois: InterVarsity Press, 1988, 79-80; my bracketed comments, based on the larger context of Bruce's analysis)
Jerome is the first of the Western Fathers to deny the inspired status of the Deuterocanon; the first to unabashedly designate them apocrypha instead . . . Jerome's new canon was an innovation -- and he knew it.But even with Jerome, there were several anomalies (or changes of mind or vacillations?), of such a nature that the would shock many a Protestant who rely on him as a "champion" in opposing the Deuterocanon. Gary Michuta enumerates several of these curious inconsistencies:
(Michuta, ibid., 142)
Protestant apologists often attempt to make Jerome the spokesman for a large silent majority of knowledgeable Christians in his day; this opinion is supported by no evidence whatsoever. Protestant scholars have long admitted that Jerome was essentially alone in his opposition to the Deuterocanon . . . It was also a decisive break from the practice of the ancient Christian Church.
He . . . flatly denies that Tobit is part of the canon,  although elsewhere he cites it without qualification!  . . . Jerome adopts the popular convention in his Letter to Oceanus by quoting Baruch as a voice made by "the trumpets of the prophets."  Sirach is both rejected and quoted as Scripture,  although it is formally quoted  and occasionally used without qualification.  Wisdom is also occasionally formally quoted.  Jerome even attributes the passages from Wisdom to the Holy Spirit.  Maccabees is used without distinction.  Jerome at times alludes to the Deuterocanonical sections of Daniel in his letters.  Deuterocanonical passages from Esther are likewise quoted.  . . . he lists Judith as one of the virtuous women of sacred Scripture . . . .
 Prologue to John.
 Commentary in Eccles. 8.
 Letter 77:4.
 Commentary on Isaiah, Book 2, 3:12; Letters 77:6: 108:22; 118:1; 148:2,16,18.
 Commentary on Jeremiah, Book 4, 21:14; Commentary on Ezekiel, Book 6, 18:6; and Letter 64:5.
 Commentary on Isaiah, Book 8, 24:4; Commentary on Ezekiel, Book 6, 18:6; Letter 57.1 To Pammachius; and Letter 125.19, To Rusticus.
 Commentary on Isaiah, Book 1, 1:24; Commentary on Zechariah, Book 3, 14:9; and Commentary on Malachi, 3:7 ff.
 Commentary on Galatians, Book 1, 3:2 . . . and Breviarium in Psalmos, Ps 9.
 Against Pelagians, Book 2:30; Letter 7, To Chromatius, Jovinus and Eusebius.
 Letter 3, 1 To Rufinus the Monk; Letter 22,9-10, To Eustochium; Letter 1, 9 to Innocent.
 Letter 48, To Pammachius, 14. Letter 65,1.
(Michuta, ibid., 149-150; again, my own footnote numbering)