Permethrin is a common constituent in some household insecticides. This study examined the effects of this chemical on the testicular histology of exposed rats. Fifteen adult male Wistar rats were subgrouped into a control and two treatment groups. The controls were fed on normal rat feeds, whilst the diet of animals in the two treatment groups was mixed with 500 mg/kg and 1000 mg/kg Permethrin respectively. An increase in body weights and organ weights was observed in the animals in both treatment groups. Various degrees of histological alterations in the structure of their seminiferous tubules were also observed in comparison with the control group. These abnormalities included disruption of the normal architecture, reduction in the population of mature sperm cells, wider luminal diameter and reduced interstitial spaces. These effects could impair the fertility potential of male subjects.