The reproductive biology of black-bellied anglerfish, Lophius budegassa Spinola, 1807, was described for the first time in the Saros Bay, in the North Aegean Sea, between September 2006 and September 2008. A total of 862 specimens (15.7-107.0 cm) was sampled. Sex-ratio, spawning period and length at first sexual maturity were determined. The F:M sex-ratio was close to 1.5. Using gonadosomatic index and gonadal macroscopic observation, the spawning period was estimated to occur between December and March. Length at first sexual maturity was 42.5 cm for males and 58.8 cm for females.