Gametogenesis of brown trout Salmo trutta caspius was studied during the period of the first sexual maturation at the establishment of the brood stock at Federal artificial selection-genetics center of fish breeding «Ropsha». In females, the period of previtellogenesis in the oocytes of elder generation lasts till the age of 19-20 months, and the period of vitellogenesis till the age of 45 months. After that, the maturation of all the individuals studied was observed. Sexual maturation of the part of males took place at the age of nearly 21.5 months and in all of the males at approximately 35.5 months and again at the age of 45.5 months. Since the males could not spawn alone by themselves, the elimination of all the volume of ripe spermatozoa was observed in their gonads two or three times. The growth rate was not high, which is characteristic of salmonid fishes at the establishment of brood stocks; at the age of 45,5 months, when the fishes of both sexes reached sexual maturity, their body mass varied ath the range of 128 to 454 g. The dwarf males were not observed in the experimental group, because the growth rate did not differ in males and females during all the period of growing.