Studies have reported that paradoxical sleep deprivation (PSD) caused a reduction in testosterone level in animals as well as in healthy men. Sleep has been described to provide an anti-oxidative function, therefore, oxidant-induced damage may play a role in testosterone reduction caused by PSD, as such, antioxidant such as vitamin E (VE) or melatonin (M) would be expected to have a protective effect on steroidogenesis. The effects of vitamin E (200mg/kgBW) and melatonin (10mg/kgBW) on testosterone concentration were examined in sleep deprived rats. Thirty six Wistar rats (Male, 150-200g, n=5) were randomly distributed into one of the following groups: A control group (C), SD, VE, VE+SD, M and M+SD. SD, VE+SD and M+SD were sleep deprived for 20 hours using the modified multiple platform method (Nunes and Tufik, 1994) between the hours of 2:00pm and 10:00am the next day for twenty days while C, VE and M remained in the control chamber for the same duration. On the 21st day, all animals were sacrificed using cervical dislocation. Serum levels of testosterone and LH were determined. Histological assessment of the testes was also done. Values are mean ± SEM and compared with student’s t-test. P<0.05 is significant. There was a reduction (P<0.05) in the testosterone concentration of SD rats (0.64±0.5ng/dL) as compared to C (3.32±0.5ng/dL) while testosterone concentration in SD+VE (3.22±1.0ng/dL) as compared to SD group increased (P<0.05) and as compared to C (3.32±0.5ng/dL) showed no significant difference. Testosterone level in M+SD (1.56±0.4ng/dL) as compared with SD was not significantly different but was lower than in C (P<0.05). When the concentrations of LH were compared, the only association seen was the reduction (P<0.05) in M+SD group (7.32±0.3ng/dL) as compared with SD (8.93±2.3ng/dL). Testicular section of SD group showed several seminiferous tubules with lack of germinal cells. Those of the SD+VE showed normal seminiferous tubules. M+SD testicular section showed about 90% seminiferous tubules with lack of germinal cells and some tubules showed sertoli cell syndrome. The results showed that vitamin E, but not melatonin prevented the reduction in testosterone level caused by sleep deprivation as well as protected the testicular cytoarchitecture. It cannot be said whether or not that oxidant-induced damage is involved in the mechanism of reduction of testosterone by sleep-deprivation since both anti-oxidant did not exert similar effects. It is therefore concluded in this study that vitamin E may have a protective role against testosterone reducing effects of sleep deprivation in Wistar rats.