The Mekong Delta is the most productive region for fish farming in Vietnam. Among the most cultured species, the Red Tilapia is important for local consumption. Streptococcosis is a septicemia disease affecting both captive and wild populations of freshwater and marine fish species throughout the world, including Red Tilapia (Oreochromis sp.) Little is known about the occurrence, virulence determinants… of the streptococcosis in Tilapia in the Mekong Delta, Vietnam. Our study aims to determine the occurrence of Streptococcus agalactiae and Streptococcus iniae, and the virulence genes of the isolated strains. The obtained results showed that: (i) S. agalactiae was detected in all of study cases; (ii) Variant results were found for differences of virulence genes of S. agalactiae; (iii) Five profiles of virulence genes were detected at different rates.