Information is given on the age structure and growth, length at first maturity, annual cycle of gonad development and diet of the Flatsnout Goby, Neogobius platyrostris (Pallas, 1814), in the Black Sea of Turkey. The maximum age was found to be 5 and 6 years for males and females, respectively. The von Bertalanffy growth parameters were estimated from the mean age-length data for males and females (males: L infinity = 21.7 cm; females: L infinity = 16.3 cm) and the growth performance indices were calculated for males phi' = 4.21 and for females phi' = 4.03. The estimated length at first maturity was 9.29 and 7.50 cm for males and females, respectively. The spawning season was between March and June. Total fecundity ranged from 103 to 990, with an average of 553 +/- 82 ripe eggs/fish. The Flatsnout Goby feeds on a wide variety of prey items, particularly on Gammaridae, Braehyura, Pisces and lsopoda.