Smoking is associated with oxidative stress. Smoke derived oxidants are a major factor in inflammatory reactions to cigarette smoke. These oxidants can alter antioxidant defenses, and can up regulate inflammation by a number of mechanisms leading to extensive oxidative damage and therefore a cumulative effect of smoking and chronic periodontitis on oxidative stress markers needs to be addressed. Smoking aggravates the intensity of Periodontitis and exacerbate the oxidative stress in chronic periodontitis compared to the non-smokers. Superoxide dismutase (SOD) is an antioxidant enzyme that acts against superoxide, an oxygen radical that is released in inflammatory pathways and causes connective tissue breakdown. This enzyme is released as a homeostatic mechanism to protect the tissues, and it can be detected in extra- and intracellular compartments. Therefore this study was undertaken to comparatively assess the SOD levels in blood and saliva of chronic periodontitis patients withand without smoking habits.