We analyzed 242 individuals from the Valley of Mexico, including the larger and more cosmopolitan city of this country. They were PCR-typed for 15 STR loci with the AmpFlSTR Identifiler PCR Amplification Kit (Applied Biosystems). Allele frequencies for each STR were estimated and compared to previous reports. Genotype distribution by locus and by two-loci combination was in agreement with Hardy-Weinberg expectations for all fifteen STRs. This STR system in Mexican-mestizos presented a combined probability of exclusion (PE) and discrimination (PD) longer than 99.999%, respectively.