Population representative short tandem repeat (STR) allele frequencies are crucial for proper probabilistic interpretation of DNA forensic evidence. STR allele frequencies also provide information about the genetic diversity of a given population. The Lebanese population is characterized by the presence of more than 18 religious communities that have high recorded rates of endogamous and consanguineous marriages, where the choice of marriages is mainly influenced by their respective geographical distributions and religious affiliation. These factors could have led to an increase in complex DNA cases, whereby high numbers of STR markers are needed to help clear the case. Allele frequencies for 23 STR loci in the Lebanese population were recently estimated and published. The present study aims at estimating the STR allele frequencies for five supplementary STRs, namely, the LPL, F13B, FESFPS, F13A01, and Penta C STR markers, which are mainly used to resolve complex kinship investigations. A DNA database representative of the Lebanese population that comprises 505 Lebanese unrelated individuals was used to amplify the five STR systems, using the CS7 kit released by Promega. The allele frequencies for these STR systems were estimated, and a significant departure from the Hardy–Weinberg equilibrium was detected after Bonferroni correction for multiple tests at locus LPL, F13A01, and Penta C. The newly added systems appeared to have variation in their discriminative power among Lebanese individuals. Penta C showed the highest power of discrimination, whereas FESFPS showed the lowest power of discrimination. The estimated frequencies and population data could provide local DNA relationship testing laboratories with additional tools that help resolve complex DNA cases. [ABSTRACT FROM AUTHOR]