Three RecA-like proteins were detected in bovine meiotic cells using antibodies against Escherichia coli RecA protein. After isolation and purification of these RecA-like proteins their molecular weights appeared to be equal to 37, 70 and 130 kD. The 37 kD protein accompanies all the stages of spermatogenesis up to the stage of mature spermatozoa. The 70 kD protein is detectable only in nuclei of cells at the stage of prophase I of meiotic division. These RecA-like proteins are involved in the formation of structural elements of the synaptonemal complex (SC) and are detected in the SC composition in meiotic cells not only of mammals but also of plants and insects, which suggests the evolutionary conservative character of these proteins.