The present research work has been carried out to analyze the physico-chemical characteristics of tannery effluent and to reduce the load of BOD and COD by the process of bioremediation using microorganisms. Among the physical chemical parameters analyzed TDS, TSS, BOD and COD were found to be very high. One bacterium, Bacillus cereus and one fungal species, Aspergillus niger were identified and isolated and used in the reduction of BOD and COD in the tannery effluent. Four different concentrations of untreated tannery effluents (control, 25, 50, 75 and 100%) were prepared. The experiment was carried out for 72 hrs (3 days). It is inferred from the results that Aspergillus niger found to be more effective in reducing BOD and COD than the bacterium, Bacillus sp. in the untreated tannery effluents.