In view of importance of nitrogen mineralization in sustenance of soil for agricultural production, influence of effluents of cotton ginning mill on activities of enzymes- protease and urease and two processes in nitrogen mineralization- ammonification and nitrification in a black cotton soil was examined under laboratory conditions. The soil samples with effluent discharges exhibited higher activities of protease and urease than soil samples without effluent discharges. Unlike enzyme activities, rates of ammonification and nitrification occurred at lower pace in polluted soils than in control. On the 7th day incubation, 740 μg (microgram) of nitrogen in the form of ammonia was formed from peptone in polluted soil as against 1445 μg of NH+ 4-N in control soil. About 576 μg of nitrogen in the form of N0- 3-N was recovered from polluted soil as against 1624 μg of N0- 3-N in control soil. Increase in enzyme activities and reduction in ammonification and nitrification could be attributed to proliferation of fungi and decrease in population of bacteria in polluted soil.