Effect of sub lethal concentration of pyrethroid pesticide Fenvalerate on Whole body, Ovary and Albumen gland of a freshwater snail, Bellamya bengalensis was evaluated. The biochemical analysis for 1th, 7th and 15th days exposed snail was made in the present work. The amount of biochemical components was greatly influenced by Fenvalerate in 15th days in all tissues in reproductive period than post reproductive and pre reproductive period. The ascorbic acid level decreased significantly in exposure to pesticide.