Numerous toxicological studies have gained increasing interest in order to understand the impact of mercury on aquatic communities especially fish. In the present study bioaccumulation of heavy metal mercury was tested in the selected organs viz. muscle, gills and liver of the commercially important fish Asian seabass Lates calcarifer. Fishes were exposed to sublethal concentrations of 5% (0.05ppm), 10% (0.1ppm) and 15% (0.2ppm) mercury for 15, 30, 45 and 60 days of experimental period and were examined for the determination of mercury in selected organs. The result shows the order of accumulation of Hg in the the seabass tissue was Liver> gill> muscle. The accumulation of mercury in the liver tissue was significantly higher than the muscle and gill tissues. Thus the result shows that accumulation of mercury in seabass L. calcarifer tissues is dose and duration dependant.