Nitrogen mustards (HN) and sulphur mustard (SM) are potent alkylating blister inducing chemical warfare agents. Single 1.0 LD50 dose produced a progressive fall in body weight from second day onwards in all groups of mustard agents exposed animals. Histological examination of spleen, liver, skin and kidney revealed significant histopathological lesions in nitrogen mustards and sulphur mustard. These lesions include granulovascular degeneration with perinulear clumping of the cytoplasm of hepatocytes and renal parenchymal cells.Renal lesions were characterized by congestion and hemorrhage. The maximum toxic manifestation were noted in spleen and skin of HN-3 exposed mice while sulphur mustard reported maximum toxicity in liver and kidneys. The study suggests both nitrogen mustards and sulphur mustard to be extremely toxic by percutaneous route based'on histopathological observation and can contributed to earlier reported free radical generation by these toxicants. ©Triveni Enterprises, Lucknow (India).