The ability to identify mate-specific DNA renders Y-chromosomal STR systems an invaluable help in cases of rape, other sexual assault as well as in kinship testing. The "PowerPlex Y System" is a recent kit by Promega, that coamplifies the repeat regions of 11Y-STRs loci. In the present study, we analyzed the allelic distribution of Y-STRs loci in around 300 unrelated males belonging to the three populations of Calabria region. (C) 2004 Elsevier Ireland Ltd. All rights reserved.