Overfishing and threat of extinction globally has been a topic of concern in the fisheries sub-sector over the years. This study assessed some aspect of the biology of Brycinus macrolepidotus in Akomoje reservoir, lower River Ogun, Nigeria. A total number of 838 fish specimens were collected bi-monthly for a nine month period from commercial catches using cast nets and long line. A total number of 51 mature female were selected for fecundity analysis which was limited to only sexually gravid female fish. Length and weight of experimental fish were measured. Data were subjected to analysis of variance (ANOVA), descriptive and inferential statistics. Correlation statistics was carried out to ascertain relationship between absolute and relative fecundity with length and weight of fish. Length and weight of experimental fish ranged between 14.5-39.4 cm and 938-1956 g. The relative fecundity ranged between 441 and 3,597 eggs with a mean of 1,702±0.16 eggs while absolute fecundity ranged from 5,838 to 39,208 eggs with a mean of 14,326±0.52 eggs. Strong positive relationship existed between total length and absolute fecundity (r= 0.74), and relative fecundity (r = 0.81). The reproductive potential of the species in this water body showed the ecological suitability of the species to its environments and to its thriving fisheries. The skewed sex ratio observed is an indication of threat to the species abundance in the lower River Ogun.  Therefore, the habitat should be monitored towards sustainable methods of managing the stock in the reservoir.