Microbial diversity constitutes the most extraordinary reservoir of life in the biosphere that we have only just begun to explore and understand. A preliminary investigation on the microbial diversity of paper mill effluents organic wastes from the landfill site of Cachar Paper mill, Panchgram, South Assam, the isolation and characterization of native microbes on different media may generate information on the nature, characteristics, and degrading efficiency of various hazardous wastes by the micro-organisms. Sludge samples were collected randomly from paper mill solid wastes dumping sites and their physico-chemical characteristics such as pH, moisture content, NPK and Cellulose content were determined. The qualitative analysis of species in microbial community was undertaken. The isolated bacteria and fungi were screened for their cellulase activity, characterized and identified. The study revealed that bacterial isolates showing higher zone of cellulolytic activity belong to Bacillus, Pseudomonas and Serratia spp, while fungal isolates mostly belong to Aspergillus and Penicillium spp .The isolates have also shown a wide range of pH and temperature tolerance. The study has suggested that the paper mill waste site harbors various microorganisms that are active in cellulose breakdown.