Population data studies were carried out on a Caucasian population from North-East Spain (n = 129-292 individuals) for 13 PCR-based polymorphic DNA loci: six short tandem repeat loci (HumTH01, HumTPOX, HumCSF1PO, HumF13A01, HumFES/FPS, HumvWFA31), the six PM loci (HLA-DQ alpha, LDLR, GYPA, HBGG, D7S8, GC) and one variable number tandem repeat locus (D1S80). The genotypes distributions were in accordance with Hardy-Weinberg expectations. The combined use of the 13 polymorphic systems provides a high power of discrimination and power of exclusion for use in forensic casework and paternity testing.