Diethylstilbestrol, an estrogen, was administered through diet to fingerlings of common carp,Cyprinus carpio at concentrations of 0, 1, 3 and 5 ppm over a period of 98 days and its effects on growth and food conversion efficiency were evaluated. The experiment was conducted in 12 cement cisterns of 25 m2 area each. Fishes were fed daily at the rate of 5% of body weight. Diethylstilbestrol incorporated diets induced faster growth and better food conversion efficiency as compared to the control. Among the dosages tried, 3 ppm treatment yielded the best growth. The faster growth in diethylstilbestrol treated groups was significantly different (P<0·05) from that of the control.