Lipid peroxide plays an important role in smokers. Increased epithelial permeability produced by cigarette smoke is likely to be mediated through depletion of sulphydryl proteins (-SH) and antioxidant capacity. The oxidant burden in the lungs is enhanced in smokers by the release of ROS from macrophages and neutrophils. Oxidants present in cigarette smoke can stimulate alveolar macrophages to produce ROS some of which attack neutrophils and other inflammatory cells into lungs. 60 smokers with smoking history 20 pkts /year were included in the study.100 healthy non-smokers__ampersandsignrsquo; were served as controls. Their base line clinical examination, malondialdehyde (MDA), sulphydryl proteins (-SH), superoxide dismutase (SOD) and total antioxidant capacity (TAC) were measured. The mean malondialdehyde levels in the patients at base line were high (P__ampersandsignlt; 0.001) than Controls. The sulphydryl proteins, superoxide dismutase and total antioxidant capacity were low (P__ampersandsignlt;0.001) in the smokers compared to controls. We found decreased levels of sulphydryl proteins and increased levels of lipid peroxide (MDA) in smokers. Thus the present study confirmed the existence of oxidative stress and alteration in enzymatic and nonenzymatic antioxidant (-SH Proteins) status.