Reproductive function in male is suppressed by psychogenic or somatic stress. Epidemiological evidences emphasize that oxidative stress plays an important role in the etiology of male infertility. Antioxidants may act at different levels in the oxidative process by scavenging initiation of free radicals and protect against oxidative stress and prevent damage of cells. Group1: Normal Control animal received Distilled water, Group 2: Positive control (Only Stress), Group 3: Stress + Low dose NAC (50mg/kg/day), Group 4: Stress+ Intermediate dose NAC (100mg/kg/day), Group 5: High dose NAC (200mg/kg/day). All the drugs were given through orogastric tube before half an hour subjected to stress. Rats were exposed to Immobilization (IM) stress daily between 10.00am to 12.00pm for 15days. Effect of IM stress on organ indices, sperm quality and testosterone level were studied. IM stress significantly decreased the whole body weight, extreme significant reduction in sperm count, motility and viability in the stress group when compared with the corresponding control group of animals. The NAC very significantly improved the body weight, sperm count, motility and viability at low dose, Intermediate dose, however at high dose decreased bodyweight but it was insignificant. Our results suggest that NAC supplementations at low and intermediate doses have improved the stress induced reproductive changes. However the high dose of NAC has not shown any improvement in comparison with intermediate dose, rather high dose have shown deleterious effects on sperm quality