The present study was designed to compare the responses in three different tissues (gill, liver and muscle of freshwater fish, Nile tilapia (Oreochromis niloticus) exposed to a synthetic pyrethroid, cypermethrin. Fish were exposed to lethal concentration (7.5 μg/L) for 2, 5, 7 and 9 days and, sublethal concentration (1.5 μg/L) for 7, 14, 21 and 28 days, and the alterations observe the enzyme activity levels were determined. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and glutamate dehydrogenase (GDH) activities were increased in all the tissues with an increase in the time of exposure. However, under sublethal concentration of cypermethrin for 14, 21 and 28 days, a decreasing tendency was observed in all the three tissues. The tissue damage specially the liver and muscles are responsible for the increased level of amino transfereae in Oreochromis niloticus. Hence, the increased level of enzymes could be used as an effective biomarker in cypermethrin exposed and which is also concentration dependent.