Broiler chicks were kept on feeds amended by the addition of 240 mg monensin and 15 mg selenium with or without 200 mg vitamin E/kg. After 12 days, birds in different groups were orally administered three doses of 250 mg monensin and 5 mg selenium/kg body weight. In the second experiment, after four weeks of adaptation on amended feeds, similar groups were orally administered 40 mg monensin and 1 mg selenium/kg body weight on alternate days for four weeks. Monensin increased the liver iron level. Selenium increased the hepatic levels of selenium and iron while variable degrees of depression occurred in copper, zinc, manganese and magnesium levels. Concurrent administration of monensin and selenium significantly increased the liver selenium levels. A marked decrease in body weight and increased mortality were recorded due to concurrent administration of monensin and selenium.