Zinc (Zn) is important for male mammalian reproduction. In this study, we sought to clarify the role of Zn in heat-induced testicular damage in mice. Eighteen mice were divided into either control (con), heat (heat) and heat plus Zn (H+Zn) treatment groups, and fed diets containing 60 (con and heat groups) or 300 (H+Zn group) mg/kg Zn sulfate for one month. Mice in the con group were then maintained at 25°C, while mice in heat and H+Zn groups were exposed to 40°C for 2 h daily, for eight days. Mouse testes and serum from each animal were analyzed.