In the present study, the effect of sodium selenite on lead induced toxicity was studied in Wistar rats. Sodium selenite and lead nitrate were administered orally for 28 days to streptozotocin induced diabetic and non-diabetic rats. Eight groups of rats were used in the study: control, sodium selenite, lead nitrate, lead nitrate + sodium selenite, streptozotocin-induced diabetic-control, diabetic-sodium selenite, diabetic-lead nitrate, diabetic-lead nitrate + sodium selenite groups. Serum biochemical parameters, lipid peroxidation, antioxidant enzymes and histopathological changes in liver tissues were investigated in all groups. There were statistically significant changes in liver function tests, antioxidant enzyme activities and lipid peroxidation levels in lead nitrate and sodium selenite + lead nitrate treated groups, also in diabetic and non-diabetic groups. Furthermore, histopathological alterations were demonstrated in same groups. In the present study we found that sodium selenite treatment did not show completely protective effect on diabetes mellitus caused damages, but diabetic rats are more susceptible to lead toxicity than non-diabetic rats. (C) 2015 Elsevier B.V. All rights reserved.