In this study, the performance of anaerobic baffled biodigester installed in different regions of South India was evaluated for black water treatment. The evaluation was based on the vendors, establishment, impact of different sampling methods (grab and com-posite sampling) and the application of post-treatment unit. The treatment efficiency of the digester was as-sessed in terms of removal of organics (biological oxy-gen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and pathogens (faecal coliform). The maximum removal rate of COD, BOD and TSS was found to be in the range of 70-75%, 68-80% and 55-75% respectively. Variations were ob-served between the grab and composite samplings with respect to the removal efficiency of organics, sol-ids and pathogens. There was no significant difference in the performances of anaerobic biodigesters in-stalled by different vendors in South India. The appli-cation of post-treatment unit such as gravel bed/reed bed after biodigester facilitated the removal of residu-al organic pollutants and provided better quality out-let water. The results indicated that the performance of anaerobic baffled biodigesters varies based on the number of users, location, usage pattern and the post-treatment unit installed. © 2020, Indian Academy of Sciences.