In this study, the species composition and distribution of cyanobacteria from Dau Tieng Reservoir were investigated. The identification results were revealed 38 species of cyanobacteria belonging to three orders,Chroococcales, Nostocales and Oscillatoriales. These cyanobacterial species occured with a wide range in size and ecological habitats, from picoplankton to microplankton and possessed the characteristic from planktonic to benthic living. Cyanobacterial distribution was homologized through the surface of the Dau Tieng Reservoir. Four recoded species of cyanobacteria from Dau Tieng Reservoir, viz. Microcystis smithi - Anabaena bothai, A. flos-aquae and A. torques-reginae are described and iIIustrated. Further investigations on ecology as well as physiology and toxicity of cyanobacterial isolates in Dau Tieng reservoir are recommended.