The present study was conducted to determine the gonadal differentiation of male and female fish in Tor grypus. In this study, 200 litter larvae in 1-10 cm size with an average weight of 3.5 ± 2.3 grams were sampled every 14 days from March 2011 to December 2012. In December, larvae were transferred to the laboratory. Standard procedures for histology, dehydration, clarification and paraffin were stained with Hematoxylin and Eosin staining methods. Then a 5 micron section was made of them and examined by a light microscope equipped with a monitor and camera. Pear-shaped male gonads were seen with a single mesenteric barrier (the future testes of the Shirbut) and in the female ducklings fed to the peritoneum on both sides (the future ovaries of the Shirbut). Germ cells with gonocytes (sexual cells) were visible at 7 cm for male 152 days after hatching. In fish, the first symptoms of morphologic diagnosis appeared in 113 days after hatching, in fish with a body length of 4.2 centimeters. On the 117th day after hatching, the first ovarian cells appeared in the 3.5cm material. The final formulation of the gonadal microscopic structure in males with a length of 10 cm in 300 days and in materials with a length of 9 cm in 217 days occurred, indicating that the final formulation in the materials Males occur sooner rather than later. In the 6-6 -6-centimeter, the distinction was completed at 145-113 days after hatching, with the advent of the first symptoms of cytological differentiation. In total, sexual maturation were observed in males 300 days after hatching and in females earlier than males and 217 days, which should be considered in artificial proliferation.