Oral administration of androgens to 1-day-old Cyprinus carpio produced a sterile/male dominated and female-free population. The female/sterile dominated and male-free population could be manipulated through the use of estrogens. Among the androgens used in the present study, 17 α-methyltestosterone (MT) at 300 mg/kg diet for 30 days resulted in the occurrence of maximum males. Similarly, the use of 17 β-estradiol (E 2 ) at 400 mg/kg diet for 30 days caused the occurrence of maximum females. The administration of 300 mg/kg diet of 5α-dihydrotestosterone (DHT) among the androgens and 400 mg/kg diet of E 2 among estrogens led to the production of maximum sterility. Males and females produced by hormonal treatments were different from normal males and females in having greatly suppressed gonads. The 30-day treatment with 200 mg/kg diet of DHT also resulted in higher growth rates, higher eviscerated body weight and higher carcass protein content of the fish. Although the stocking density of the fish during hormonal treatment did not have any effect on sex composition, it affected fish growth during the post-treatment culture of the fish in grow-out ponds. The fry treated with the hormones at a stocking density of 3400/m 3 grew maximally during the post-treatment rearing period.