The polymerase chain reaction (PCR) amplification of STR loci has already proven to be a method of choice for large-scale typing of DNA samples in which the conventional restriction fragment length polymorphism (RFLP) technique is ineffective. A quadruplex PCR including HUMvWFA31A, HUMF13A01, HUMTH01, and HUMFESFPS STR loci is used successfully for routine forensic application in the authors' laboratory; however, the need to increase the discrimination power of the PCR systems used prompted the authors to develop a second system of a pentaplex PCR for the analysis of four additional STR loci (HUMD8S1179, HUMD18S51, HUMD21S11, and HUMFIBRA) and the sex determination by amplification of a segment of the X-Y homologous Amelogenin gene. Allele and phenotype frequencies for these four STR systems were obtained by multiplex amplification, from approximately 200 randomly selected and unrelated French Caucasian individuals. Statistical calculations for these phenotype distributions met expectations for Hardy-Weinberg equilibrium. Furthermore, the French allelic frequencies of D18S51, D21S11, and HUMFIBRA loci were compared with the data obtained by the Forensic Science Service for the British Caucasian population and proved to be similar. 3 tables, 1 figure, and 15 references