The ant genus Crematogaster Lund, 1831 is recorded for the first time from the Late Eocene Rovno amber, Ukraine (Priabonian stage, 33.9–37.8 Ma). C. primitivasp. nov. is described based on single male. It well differs from males of the extant species by the 13-segmented antennae (vs. 11–12-segmented in modern species). By this feature it resembles the fossil C. praecursorEmery, 1891 described from the Sicilian amber (Early Oligocene, Rupelian stage, 27.8–34.9 Ma), but differs from that species by its distinctly longer antennal scape and by some details of the forewing venation. Only one other fossil Crematogaster species is known – C. auroraLaPolla et Greenwalt, 2015, which was described based on the imprints of two queens from the Middle Eocene Kishenehn Formation, USA (ca. 46 Ma); however, we consider that the ascription of this species to Crematogaster is somewhat questionable.