The study was carried out at Lekki Lagoon which is part of the Lagoon system in the Western coast of Nigeria. Samples of Schilbe mystus were obtained from Epe fish depot for six months (January to June). A total of 337 specimens were examined. Identification of this species was done using the technique proffered by Olatunde (1977). Fecundity was estimated by using the gravimetric sub-sampling method (Dry technique). Overall sex ratio of 1.0: 2.5 in favour of the female was obtained. The sex ratio varies monthly. The highest sex ratio in June was associated with breeding activities. Condition factors (K) were found not to vary with stages of gonad maturity in both sexes while Gonadosomatic index (GSI) increased with the stages of maturity. Fecundity ranged from 10,906 to 23,700 eggs. Breeding condition was attained during the rains.