PURPOSE: Testicular torsion followed by ischemia results in variable degrees of infertility and until now there appears to be no effective way to recover it. Testosterone participation in the maintenance of male sexual organs and spermatogenesis led us to hypothesize that intratesticular administration could recover ischemic injury. MATERIALS AND METHODS: We divided 40 Wistar rats in 2 groups, of 20 each. One group was control and the other underwent a 120-minute testicular ischemia by means of a vascular clamp on the left spermatic cord. Each group was further subdivided in 2 subgroups. The first one was observed and the second received intratesticular testosterone 25 mg. starting on the third day after injury and during the next 7 consecutive days. Half the animals were sacrificed 30 days after injury and the remaining ones after 60 days. Weight, volume, number of seminiferous tubules, histology and spermatogenesis of the same side and contralateral testes were examined. For statistical analysis ANOVA and Fisher's tests were applied. RESULTS: It was found that testosterone was capable of acting upon volume and weight of the left testis (p=0.0001). The animals receiving intratesticular testosterone showed lower testicular weight and volume after 30 and 60 days, respectively. This subgroup also showed a higher number of seminiferous tubules, modified histology and absent spermatogenesis suggesting testicular atrophy. CONCLUSIONS: We concluded that intratesticular injection of testosterone 25 mg. once a day during 7 consecutive days after transitory testicular ischemia causes ipsilateral testis atrophy. The animals in control group showed testicular histological recovery 60 days after injury. There were no significant histological differences in the contralateral testes.