Abstract- Nitrogen-fixing and phosphate-solubilizing bacterial  diversity and population dynamics in the Acrisol rhizosphere of sugarcane grown in Tay Ninh province, the South-Eastern Vietnam was studied. Soil rhizosphere samples were taken in seven districts (sites) of this region. Physical and chemical characteristics of the soil samples as well as total nitrogen-fixing and phosphate-solubilizing bacteria counts were determined by drop plate method together with 16S rRNA gene fragments amplified from DNA using eubacterial universal primers (27F and 1492R). A total of 331 isolates were isolated on two media (Burk’s N-free and NBRIP) and all of them have ability of nitrogen fixation and phosphate solubilization together with IAA  biosynthesis. Population of nitrogen-fixing and phosphate-solubilizing bacteria correlated with organic matter content in soil very closely