Three fractions of repeated sequences with different thermal stability after reassociation and zero time and single copy fractions as well were isolated from a sterlet (acipenser acipenser) genome. Repeated sequences with different thermal stabilities are organized as homogeneous families not reassociating with one another when being repeatedly annealed. These fractions consist of the similar kinetic components; the exception is the slowly reassociating component which is found only in the low temperature fraction. The sterlet repeated sequences were also fractionated according to their length on agarose A-50 columns. The long (no less than 1350 nucleotides) sequences are heterogeneous by extent of their divergency, some part of them being highly divergent and contain sequences that are homologous to repeated sequences with low thermal stability. A suggestion is made that long and short repeated sequences in the sterlet genome are partly shared. The short (about 400-600 nucleotides) repeated sequences in the sterlet genome are interspersed within single copy ones.