An experimental study was conducted to evaluate the hepatotoxic effects in the progeny of dams treated with methimazole, monocrotophos (MCP) and lead acetate. Female pregnant albino rats of Wistar kyoto strain were divided into five groups and treated as follows, from day 3 of pregnancy till weaning of pups on postnatal day (PND) 21. Group 1 served as sham control, group 2 received methimazole 0.02% in drinking water, group 3 received MCP (0.3 mg/kg orally), group 4 received lead acetate at 0.2% in drinking water and group 5 received MCP + lead acetate. Thyroid hormone profile was recorded on 14 thday of gestation in dams. Eight pups from each group were euthanized on PND 21 and 90, and liver tissues were collected for analysis. Thiobarbituric acid reactive substances (TBARS), protein carbonyls and reduced glutathione (GSH) of liver were studied on PND 21 and 90, while the activities of Na +/K+ATPase and Mg 2+ATPase in the liver were studied on PND 90. T3, T4, GSH, Na+/K+ATPase and Mg2+ATPase were significantly (P<0.05) decreased, while TBARS and protein carbonyls were significantly (P < 0.05) increased in all the test groups as compared to group 1. From this study, it is concluded that both MCP and lead acetate have a possible influence on thyroid gland of dams as the thyroid profile was altered significantly and the hepatotoxic effects were comparable to those induced by methimazole.