Propofol, which is widely used as an intravenous anesthetic, has been shown to have an antioxidant activity on several tissues. This study was designed to investigate the prevention of reperfusion injury with propofol after testicular torsion. Five groups of rats (seven in each group) were used. Animals in the control group (group I) did not received any treatment, while animals in the sham group (group II) underwent scrotal incision and testicular fixation only. After 2 h of 720 degrees left testicular torsion in groups III, IV and V, subsequent detorsion was done for 2 h in groups IV and V. Propofol (50 mg/kg) was injected transperitoneally 30 min prior to detorsion in group V. Both testicles in all rats were retrieved and tissue malondialdeyhde (MDA) level, which is a measure of the amount of free oxygen radicals, and enzymatic activity of xanthine oxidase (XO), which converts hypoxanthine to xanthine and uric acid were studied. In addition, tissue catalase (CAT) and glutathione peroxidase (GSH-Px) activities, which are endogenous scavenger enzymes, protecting tissues against free radicals, were studied. Additionally, histological evaluations were performed after hematoxylin and eosin staining. Testicular MDA levels, and XO and CAT activities were higher in the torsion group compared to sham control group (P<0.05). Detorsion caused a further increase in MDA levels, contrasting with a decrease in the levels of XO activity, while CAT activity was not changed. Pretreatment with propofol prevented a further increase in MDA levels and significantly decreased CAT activity following detorsion. GSH-Px activities were not effected either by torsion/detorsion or propofol pretreatment. Histologically, torsion caused some separation between germinal cells in the seminiferous tubules, which became much more prominent in the detorsion group and attenuated with propofol pretreatment. There was no significant change in any of the above-mentioned enzymatic activities nor were there histopathological changes in the contralateral testicle in any groups. It is concluded that biochemically and histologically reperfusion injury occurs in the ipsilateral testis following detorsion up to 2 h. Preference of propofol for anaesthesia during the detorsion procedure may attenuate such reperfusion injury.