Frequency data of 20 polymorphisms (13 autosomal and 6 Y-chromosome STRs and the Alu-insertion YAP) were determined in a sample of 124 unrelated Jewish individuals from Ashkenazi, Sephardic, North African and Oriental origin. The a priori statistical power of the set of studied loci was highly discriminating (PD=1 in 2.393 E+15 individuals for autosomal STRs, and a probability of finding two unrelated males with the same haplotype of less than 0.01). Some significant population differences were registered between Jews and other Circummediterranean populations in Y-chromosome loci frequencies.