The organophosphorus pesticide, monocrotophos induced toxicity in fish’s adobe has been studied to access the biochemical and hormonal disruption caused in the liver and ovary of the fish. Monocrotophos pose serious risk to biochemical parameters, enzyme activities and level of hormones in the fishes. A direct relationship between concentrations of monocrotophos, elevated cholesterol levels and depressed estradiol concentrations have been traced in the study. The elevated levels of cholesterol in the ovary apparently reflect the reduced rate of its utilization for steroid synthesis by the ovary as significant effect of pesticide. The decreased estradiol level causes decreased production of vitellogenin as well as hampers the development of oocytes in ovary of Cyprinus carpio communis which was also evident in the experiments.