Background: The effect of zinc supplementation on birth weight, litter size, total erythrocyte count (TEC), hemoglobin estimation, total leukocyte count (TLC), blood glucose level, abnormal sperm count and histopathology of testis in mice was evaluated. Methods: 45 albino mice were randomly divided into 3 equal groups viz. control group, A; 10 mg zinc/kg feed treated group, B; 20 mg zinc/kg feed treated group, C. Each group was comprised of 10 male mice and 5 female mice. Then they are allowed to breed for about 25 days. After breeding males were withdrawn from each group and treated with zinc for 30 days. Then male mice were transferred back to female cage and were allowed to breed for 25 days. Results: Mice of group B and C showed a significant increase (p<0.01) in total erythrocyte count (TEC), total leukocyte count (TLC), hemoglobin content, litter size and decreased abnormal sperm count. No significant increase in body weight, even a decrease in glucose content was recorded in group B and birth weight was found increased in group C. In the histopathological study, no significant change found with different doses of zinc supplementation except reactive cell infiltration and slight tissue degeneration in the mice fed with 20 mg zinc supplement/kg feed was recorded. Conclusion: Supplementing zinc @ 10-20 mg/kg feed was found to enhance hematological parameters, increase litter size and decrease abnormal sperm count in mice.