Objective:To investigate genotypes and serotypes of HIV‐1 variants in Russia, Byelorussia and Lithuania.Patients and methods:Sera from 20 HIV‐1‐infected individuals were tested in an enzyme‐linked immunosorbent assay (ELISA) with 19 V3 synthetic peptides, and serum HIV‐1 V3 RNA was amplified and sequenced.Results:Sequence comparison of the envelope V3 region among specimens tested revealed a 2‐29% range of nucleotide divergence, with a mean of 19%. Phylogenetic analysis clustered the V3 sequences recovered with subtypes A, B, C, D and G. All sequences from the homosexual men were shown to belong to subtype B, and all of the heterosexually infected individuals to subtype C. Sequences from the parenterally infected individuals were more heterogeneous. In the peptide ELISA three reactivity patterns were found. Serum samples from six out of seven homosexual men showed reactivity to peptides p108 or p110 representing V3 amino‐acid sequences found in US/West European HIV‐1 isolates. Serum samples from six out of seven individuals who had acquired HIV‐1 through heterosexual contacts were reactive to peptide p169. Four out of six parenterally infected patients had peak reactivity to p168.Conclusion:Distinct HIV‐1 variants were found in Russia, Byelorussia and Lithuania, which were introduced simultaneously in the mid‐1980s. This diversity was shown to be associated with the route of transmission. Homosexual men appeared to be infected with subtype B and heterosexually infected individuals with subtype C HIV‐1 variants. HIV‐1 subtypes A, C, D and G were found among parenterally infected individuals.AIDS 1995,9:435‐439