Fish culture and management frequently need the use of biometric relationships as appropriate indices for commercial culture. The present study describes the annual changes in gonadosomatic index and fecundity of the Tilapia mossambica in Chambal River at Nagda, Madhya Pradesh (India). Gonadosomatic index ranged from 0.33 to 7.29% with a mean of 2.89±0.08%. High gonadosomatic indices were recorded from March to June, which confirmed the spawning period of the fish. Fecundity ranged from 7,048 to 16,828 eggs with a mean of 12,742±132 eggs. Fecundity – body weight and fecundity body length were positively correlated. Fecundity – weight relationship was Log F=0.1243+2.74Log W (r = 0.950). Fecundity – length relationship was Log F = 0.0247 + Log 1.779 Log L (r = 0.114). Fecundity was more related to weight than length. Tilapia mossambica spawns during the summer months. The results of this study will assist in increasing the knowledge of the reproductive biology of Tilapia which is relevant in aquaculture management adequate supply as well as breeding.