The effects of different volumetric ratios of bulking agents to pulp/paper-mill sludge on composting were studied. Rice husk and corncob were used as bulking agents. Volumetric ratios of bulking agents to pulp/paper-mill sludge were used as 10:100 and 25:100. To monitor the evolution of the composting systems, routine parameters such as temperature, moisture, pH, total N, NH4 +-N, NO3 --N, total C, and C/N ratio were analyzed. The results indicated that the agro-based materials significantly affected compost maturity parameters. Moreover, the quality of the product obtained in the composting process treated with the agro-based materials achieved satisfactory stabilization and sanitation for application to land.