Many diseases are linked to damage from reactive oxygen species that occurs from an imbalance between reactive oxygen species and antioxidants, a condition called oxidative stress. Nasal polyposis is considered to be an inflammatory condition in nasal and paranasal sinus cavities and its aetiology is still unclear. The blood NO,antioxidant VitaminS and enzymes levels were found to be decreased, and MDA, levels as an oxidant increased significantly in the patient group with polyposis when compared with the control group, and there was a negative correlation between oxidative stress and antioxidants.Our Results are oxidative stress and blood antioxidants in the patients with polyposis were significantly different compared with the control group. The blood antioxidant levels decreased, and MDA levels,as an oxidant, increased significantly in the patient group with polyposis when compared with the control group. The current study demonstrates that there is strong evidence related to oxidative stress in the pathogenesis of nasal polyposis, and antioxidants can have a preventive role in free radical mediated damage in nasal polyposis.