Haplotype and allele frequencies for the 12 Y-STRs were determined in a population sample of 124 unrelated males--members of the Lithuanian minority residing in the northeastern Poland. Three of the haplotypes were encountered in duplicate, while 118 haplotypes were unique. The overall gene diversity was 0.9952. Analysis of molecular variance revealed that the Lithuanian minority can be distinguished from the autochthonous Poles, although these two populations are very close to each other. This database study provides an essential precondition for applying Y-chromosomal STRs estimates in forensic identification of male DNA and tracing of paternal lineages.