Sediment microbial fuel cells (SMFCs) are being constructed and operated to produce renewable power for remote monitoring. They are highly advantageous than typical MFCs. In this study, 2 kinds of sludge (activated sludge and anaerobic sludge) were used in SMFCs for investigating their performance characteristics such as the power density production and chemical oxygen demand (COD) removal. The performance of the SMFC with anaerobic sludge was found to be better than that of activated sludge. Experimental results revealed that the maximum power density and COD removal were reported in anaerobic sludge SMFC (10.36mW/m(2), 62%) and the activated sludge SMFC produced 3.97mW/m(2), with a COD removal of 58.2%. The dissolved oxygen values for activated and anaerobic sludge were 3.45 and 0.75ppm respectively. Control SMFC was run without sediment, and its performance was inferior compared to the SCMFCs with sludge. Generally, the anaerobic SMFC had 2.52 times better power density production than the activated SMFC and control. Moreover, the COD removal was 19% higher than the control. Results concluded that the selection of sludge plays an important role in the SMFC performance. The findings of this study will be useful for the practical applications of SMFCs in real wastewater treatment plants and energy production in the future.