Low antioxidant levels and oxidative stress due to airway inflammation may be determinant of asthma severity. The study was conducted to find the extent of lipid peroxidation and change in the levels of plasma iron in asthmatic patients with severity of disease. Study included 155 asthmatic and 156 healthy volunteers of the age groups 18-45 of either sex. Asthmatic patients were grouped into mild, moderate and severe groups on the basis of Forced Expiratory Volume in first second percent (FEV1%). Level of plasma malondialdhyde (MDA) was used as index of lipid peroxidation. A significant increase (P<0.01) in plasma MDA and plasma iron levels was found in asthmatic subjects as compared to controls. There was maximum increase in plasma MDA and iron levels in moderate asthmatic group. A positive correlation between plasma MDA and iron (r = +0.3) has been found in asthmatic patients. An increased plasma iron levels in asthmatics may contribute to aggravate lipid peroxidation.