In this study, experimentally lindane-induced histopathological changes and proliferation and/or apoptosis in germ cells in the rat testes were investigated. A total of 40 healthy fertile 3-month-old male rats were used. Animals were divided into 4 groups, each containing 10 rats. Group 1 (control) was given only pure olive oil, Groups 2, 3 and 4 were administered lindane at 10, 20 and 40 mg/kg/bw, respectively, by gastric gavage for 30 days. Microscopically, degenerative changes were observed in the lindane-treated groups. For proliferative activity PCNA immunolabelling and for germ cells apoptosis TUNEL methods were performed. Although a strong PCNA positivity in the control group was observed, a gradual decrease was noted in the lindane-treated groups especially at higher doses. Significant increases of apoptosis were seen in the lindane-treated groups compared to the control group. A decrease in testosterone concentrations was observed in lindane-treated groups compared to the control group. The study indicates that high-dose lindane intoxication contributes to the suppression of spermatogenesis through a reduction of germ cell proliferation and an increase of germ cell death in rat testes.