Acid-fast intranuclear inclusion bodies were found in the cells of the proximal convoluted tubules of the kidneys of mallards fed one, two, three or eight number 6 lead shot and maintained on cracked or whole corn and on grain-duck pellet diets. No acid-fast inclusion bodies were found in mallards fed one or three lead shot but maintained on a duck pellet ration. Dietary factors may be responsible for the failure of mallards fed a duck pellet ration to develop lead inclusion bodies when treated with one or three lead shot. The authors suggest these inclusion bodies can be used as presumptive evidence for lead intoxication in mallards.