The effect of mercuric chloride on the histo-morphology and bioaccumulation in the kidney of an Indian major carp, Labeo rohita (Hamilton) were examined after exposing the fish (15-20 cm) to three sublethal concentrations (0.033, 0.066 and 0.132 mg/L) of HgCl(2) for 30 days. Mercury deposition in kidney tissues had increased significantly with dose and exposure duration dependant manner. Several histological changes were noted in the kidney of all treated groups in compare to control group.