After informing 331 unrelated Brazilian individuals (240 Caucasians and 91 Mulattoes) and getting their consent, blood samples were collected. DNA was extracted from 5 mL of peripheral blood obtained from each of 331 volunteers by the salting-out procedure (1). PCR analysis was performed using the GenePrint™. STR Multiplex System (CTT Multiplex, Promega Corporation, Madison, WI) under conditions recommended by the manufacturer. The amplified fragments were submitted to electrophoresis on denatured polyacrylamide gels and visualized after silver staining. Allele identification was achieved by comparison of the amplified fragments with the allelic ladder included in the reagent set. Statistical analysis: gene and genotype frequencies were estimated using standard counting procedures; for comparing gene counts between samples and for testing Hardy-Weinberg proportions within each sample, Chisquared tests were used throughout. All these procedures are described in detail by Weir (2). In order to locate the categories responsible for significant values in contingency tables, the method of adjusted standardized residuals described by Haberman was applied (3,4). Tables 1, 2, and 3 summarize the frequencies and Table 4 describes the observed and expected heterozygosities. The complete data set is available to any interested researcher upon request.