Freshwater fishHeteropneustes fossilis andSarotherodon mossambicus were exposed to distillery and paper mill effluents with a view to check the hematological changes as a function of feeding/starvation and aeration/non-aeration. Increase in concentration always produced elevated values in RBCs irrespective of feeding and/or aeration. This elevation was statistically significant (P<0·05) in most of the test individuals. Fish exposed to effluents showed a dose dependent increase in WBCs (P<0·05). Maximum number of RBCs and WBCs was always noticed in the non-aerated condition. Statistical analyses confirmed that the change in number of blood cells as a function of feeding/starvation and aeration/non-aeration was not significant (P>0·05).