Producing bioenergy from the anaerobic digestion (AD) of poultry droppings (PD), press mud (PM), sugarcane bagasse (SB) and sugar beet roots and tops (SRT) could be an effective source of fuel and energy for processing sugar from sugar beet and sugarcane and for reviving and making the sugar industries profitable in Bangladesh. The total solids (TS) content is crucial for an optimum performance of the AD process. In this study, batch assays were conducted to determine the optimal TS contents on the mesophilic AD of PD, PM, SB and SRT with TS contents of 5, 8, 11 and 15%, respectively. The highest biochemical methane potential (BMP) were found 254, 121, 205 and 23 NL kg−1VS for PD, PM, SB and SRT after digestion for 90 days at TS content of 11%, 15%, 11% and 8%, respectively. The results indicate that the initial TS influenced the AD performance significantly and modeling showed that the optimal initial TS content for AD of PD, PM and SB ranged between 12 and 13%.The only exception was SRT, where an initial TS content of 8% is recommended.