Smoking is associated with high incidence of morbidity and mortality. The free radicals released during smoking thought to play an important role in forming imbalance between oxidants and antioxidants. A total number of 200 subjects comprising of 50 healthy controls and 150 cases of smokers divided into mild, moderate and heavy smokers studied. In all the subjects, serum levels of malondialdehyde (MDA) as a biomarker of lipid peroxidation and antioxidant serum vitamin C were estimated. Serum MDA was significantly increased in smokers when compared to controls. The oxidative stress level was elevated in accordance with the intensity of smoking. The antioxidant serum vitamin C was significantly decreased in smokers when compared to controls. The presence of increased systemic oxidative stress in smokers seems to be associated with current active smoking and systemic inflammation. The decrease in antioxidant levels appears to be mainly a consequence of increased oxidative stress. Hence by advising cessation of smoking and taking diet rich in antioxidants may prevent oxidative damage and prevent oxidative stress related diseases.