Population studies were carried out on the Y-specific short tandem repeat (STR) systems DYS19, DYS389I + II, DYS390 and DYS393 in a Western German population sample. Determination of the allele frequencies revealed for all these systems, unimodal distribution. The number of observed alleles varied: five for DYS19, six for DYS390, three for DYS389I, seven for DYS389II and six for DYS393. In 102 unrelated male individuals, 56 different haplotypes were found. The haplotype diversity values were similar to those of other European populations.