The toxic effect of chromium on the histology of gill and liver of Labeo rohita fingerlings was studied. The fingerlings were exposed for 10, 20 and 30 days in 10% sublethal concentration of 96 h LC50 of chromium (3.5 ppm). The gills exposed to sublethal concentration of chromium showed mild histological alterations during 10 days of exposure. However after 30 days, fusion of gill lamellae, hypertrophy and degeneration of epithelium were prominent. Liver lesions consisted of vacuolation, degeneration of hepatocytes and disintegration of cell boundaries of hepatocytes. These changes occurred predominantly in the 30 days exposure.