The article is devoted to an analysis of the suffixal and truncated suffixal variants of male Christian names in the Lutsk castle book of 1560‑1561(2013), and the identification of productive / unproductive formants in the composition of the researched names. The Polish academic I. Mytnik prepared a monograph Anthroponymy of Volynia of the 16th‑18th centuries (2010), using a wide source base – 58 manuscripts and 32 printed sources, but this 16th‑century Volyn literary heritage site did not serve as a basis for her study. Having studied the word‑formative derivatives of the male Christian names in the Lutsk castle book of 1560‑1561 we came to the conclusion that the most productive formants are ‑k(o) (67 variants) and ‑ets (40 variants); the suffixes ‑yna (10), ‑uk (9), ‑ash (6), ‑osh (4) show a slightly lower productivity. With the help of the suffixes ‑k(a), ‑yk, ‑ysh, ‑ut(a), ‑yts(a) 2 nominal variants are formed. Names with the formants ‑ok, ‑as, ‑ys, ‑os, ‑ay constitute single examples. The most commonly used names in Volyn documents from the middle of the 16th century were Yatsko / Ya(ts)ko (35 bearers), Fede(ts) / Khvede(ts) (22), Vasko / Va(s)ko (20), Hrytsko / Hry(ts)ko, Yvane(ts) (18), Le(v)ko (15), Andree(ts) / Andr± e(ts) (14), Yvashko / Yva(sh)ko, Matys (11), Mykhno, Tyshko / Ty(sh)ko, Fe(d)ko / Khve(d)ko (10). Among the truncated suffix name variants, the most productive form is ‑khno: it being attested in 9 names. While the most commonly used name is Mykhno (10 bearers).