Changes in organic C, total N, C:N ratio, activities of cellulase, xylanase and protease, and microbial population were determined during composting of different organic wastes such as mixture of sugarcane trash and cattle dung, press mud, poultry waste and water hyacinth biomass. There were losses of N in poultry waste and water hyacinth with the effect an initial increase in C:N ratio was observed which decreased later on due to decomposition. The activities of cellulase, xylanase and protease were maximum between 30 and 60days of composting in various wastes. Similar trend was observed with respect to mesophilic bacterial and fungal population. Various quality parameters like C:N ratio, water soluble C (WSC), CO₂ evolution and level of humic substances were compared after 90day composting. There was statistically significant correlation between C:N ratio and CO₂ evolution, WSC and humic substances. Significant correlation between CO₂ evolved and level of humic substances was also observed. The study shows that no single parameter can be taken as an index of compost maturity. However, C:N ratio and CO₂ evolved from finished compost can be taken as the most reliable indices of compost maturity.