This study was done to evaluate the effects of lead nitrate and mercury chloride in testis tissues of Wistar rats. Lead nitrate and mercury chloride are widely used heavy metals in industry. Oral lead and mercury administrations to adult male rats at doses 45 mg/kg bw and 0.02 mg/kg bw, respectively for 4 weeks caused a significant increasing in MDA levels and antioxidant enzyme activities (SOD, CAT, GPx and GST). The MDA levels and acivities of antioxidant enzymes was lower in rats that were administrated by lead nitrate than mercury chloride treated group. Light microscopic analyses revealed that lead nitrate and mercury chloride induced numerous histopathological changes in testis tissues of rats. Histopathological observations of the testis tissues showed that mercury chloride caused more harmful effects than lead nitrate, too. The results indicate that lead nitrate and mercury chloride have reproductive toxicity, in male rats at the tested doses. The effect which we observed applying the lead nitrate and mercury chloride together, was more greater than when we used them alone.