1 The effects of lindane on the reproductive system and its concentration in different tissues were investigated. Groups were dosed orally with 6 mg lindane/kg for 5 days or with a single dose of 30 mg/kg body weight. 2 The results indicate that the number (mio) of sperma tids counted in the testes of both treated groups 2 weeks after treatment were significantly reduced compared to the control rats. Effects on the number of sperms were observed in both treated groups, but significant differences were only revealed on those with 30 mg/kg. 3 The concentration (μg/g tissue) of lindane in adipose tissue, liver, brain and testis was determined 24 h and 2 weeks after the last treatment. Lindane was detected in the testis of both groups 24 h and 2 weeks after the last treatment. 4 Histological investigation by electron microscopy revealed a pronounced ballooning of Sertoli cells accompanied by fragmentation or complete loss of organelles. 5 According to the result obtained, it is evident that lindane passes through the testis and exerts its toxic effect.