Eight variable microsatellite loci were analyzed in terms of studying the genetic structure of different generations of a captive population of a rare endemic Russian species, the Siberian crane (Grus leucogeranus Pallas). It was shown that the founding population of natural origin (15 birds) is characterized by high genetic diversity (N(A) = 6.625, H(O) = 0.767, H(E) = 0.731) and a lack of relatedness (R = -0.079). In the total sample of descendents of the founders (122 individuals from generations F1, F1/F2, F,/F3, F2, F2/F3), this characteristic level of genetic variation was retained; however, we observed a decrease in allelic richness in some generations (F1/F2, F1/F3, F2). We found a low level of relatedness inthe sample of descendents of the founders (F1, F1/F2, F1/F3), while the relatedness was maximal (R = 0.302) in the first-generation descendents of the breeders. A small sample of breeders related to each other of generations F1 and F2 (eight birds) does not represent the entire gene pool of the founders of the Siberian Crane captive population. In view of this, we discuss the need to form a new genetically heterogeneous generation of breeders that would also include Siberian Cranes from the virtually extinct Western Siberian population.