Benthic macrofauna communities in the Mekong river were investigated on species composition, densities and biodiversity in 8 sampling stations. Results showed 109 species of aquatic invertebrates belonging to 3 great phylum: Mollusca, Arthropoda and Annelida. They are characterized by high densities with number from 202 to 3353 inds/m² and high biodiversity (the Shannon – Wiener index H’ range from 1.3 – 3.2). Results of this study indicated variety of important biological resources of benthic macro – invertebrate in the Mekong river. Hence, there should have suitable policy and exploration to conserve valuable species for economic development and scientific purpose.