Eighteen (Duroc × Landrace × Yorkshire) castrated boars,55 days of age and weighing approximately 19 kg, were used to investigate the effects of montmorillonite nanocomposite on tissue levels of lead as well as changes in blood biochemical parameters in pigs fed lead contaminated diets. The barrows were randomly assigned to one of three treatments( n = 6) including a control which were fed a basal diet based on corn and soybean meal. The remaining two groups were fed the basal diet supplemented with 10 mg/kg lead either with or without 0.5% montmorillonite nanocomposite for 50 days.Pigs treated with lead had significantly increased levels of lead in their tissues. Lead accumulated in all tissues of the body with the highest accumulation found in the hair. When montmorillonite nanocomposite was given along with lead, tissue concentrations of lead did not differ from the control. Fecal excretion of lead increased significantly in lead-exposed pigs treated with montmorillonite nanocomposite. A progressive and appreciable accumulation of lead was seen in blood with a concomitant increase in zinc protoporphyrin levels during the course of treatment. However,zinc protoporphyrin levels did not differ from the control when montmorillonite nanocomposite was administered along with lead. The activity of δ-amino levulinic acid dehydratase in blood was significantly increased in lead treated pigs compared with the control. However, in pigs treated with lead and montmorillonite nanocomposite in combination, the activity of δ-amino levulinic acid dehydratase was similar to control pigs. Our results indicate that montmorillonite nanocomposite treatment of pigs exposed to lead resulted in reduced lead concentrations in body tissues.It appears that montmorillonite nanocomposite functions by increasing fecal excretion of lead.