Allele and genotype frequencies were determined in a population sample from Catalonia (northeast Spain) for two short tandem repeat loci (HUMCD4 and HUMF13A1), using the polymerase chain reaction (PCR). After denaturing PAG electrophoresis, 6 alleles were identified for HUMCD4 in a sample of 157 unrelated individuals, and 11 alleles for HUMF13A1 in a sample of 141 individuals. No deviation from Hardy-Weinberg equilibrium was found. The HUMCD4 and HUMF13A1 loci demonstrated a heterozygosity of 0.6815 and 0.7305 respectively.