The short tandem repeat (STR) polymorphism of the locus D12S66 was amplified by PCR and analyzed by denaturing polyacrylamide gel electrophoresis followed by silver staining. Among 190 DNA samples from the Japanese population, six alleles were observed. The genotypic distribution meets Hardy-Weinberg expectations, and the heterozygosity was 52.7%. When sequences of the allelic products were compared, each allelic segment was 153-173bp in size, and contained 9 to 14 GATA tetranucleotide repeat motifs. Amplification of the locus using 27 tooth and blood stain samples as sources of degraded DNA resulted in low backgrounds and reproducible patterns, suggesting the usefulness of the application of this locus for material examination.