A population study in a sample of 211 unrelated individuals from 2 cities in North and Central Italy was carried out to investigate the short tandem repeat (STR) system HUMVWA31. Separation of PCR- amplified DNA fragments was performed by high-resolution horizontal denaturing polyacrylamide gel electrophoresis (PAGE) followed by silver staining. The 7 common alleles were found, together with a new smaller allele. Distribution of the observed genotypes did not deviate from Hardy-Weinberg (H-W) equilibrium. The power of discrimination for this locus was 0.93 and the chance of exclusion was 0.61. Good agreement was found between the allele frequencies in 2 Italian population samples and previous studies on Caucasians. The results of this study suggest that this STR system may be a useful tool in forensic investigations.