The present study was designed to investigate the effect of diazepam on the physiological changes of anxiogenic male rats. 120 male albino rats weighing 120±10g were divided into 6 groups. Control -ve (Untreated), control +ve (Treated with saline), drug (0.9mg diazepam/kg body weight), anxiety (Sleep deprived), drug+ anxiety, anxiety+ drug groups (exposed to the same conditions of drug and anxiety groups). Blood and brain samples were taken from all groups after 48 and 72 hours of anxiety. Blood was collected into two tubes, the first containing EDTA and the second without anticoagulant. Erythrocyte lysate, plasma and serum were separated and frozen at -20cº for biochemical and hormonal analysis. The results revealed that 48 and 72 hours of sleep deprivation caused depletion of SOD, CAT and GSH activities and increase of MDA levels in blood and brain of anxiogenic rats compared with control ones. The increment of plasma ACTH was also reported in anxiety group. Anxiogenic rats treated with diazepam revealed an improvement in SOD, CAT and GSH activities and depletion of MDA level in blood and brain compared with anxiety group. Plasma ACTH concentrations was decreased also in anxiogenic rats treatmed with diazepam. It might be referred that treatment with diazepam minimizing deleterious effects of sleep-deprivation induced oxidative damage suggesting its anti oxidative effect, and its inhibitory effect on the hypothalamic pituitary adrenal axis (HPA) activity.