This article provides an introduction to and a transcription as well as English translation of a previously unknown Armenian fragment of the Gospel of Mark (15:4b–7a, 11b–14a), which is currently kept in a private collection in the Middle East. The fragment was extracted from the binding of a sixteenth-or seventeenth-century Garšūnī codex that probably came from Diyarbakir in Turkey. The Armenian text is inscribed in the erkat‘agir uncial (“iron-forged letters”) that can approximately be assigned on paleographical grounds to the late tenth or eleventh century CE. The paper compares the textual variants of the newly identified fragment against the old Armenian text of the Gospel of Mark published by Johannes Zohrap in 1805. Although the text usually agrees with the Zohrap edition, at least one notable difference occurs in Mark 15:5. Finally, the attempt to reconstruct the fragment codicologically raises some questions concerning the format of the manuscript to which it originally belonged.