Cigarette smoking is major risk factor for many illnesses including cardiovascular diseases. Smoking is known to have adverse effects on endothelial function. This leads to thrombotic episodes by enhancing platelet aggregation. Raised C-reactive protein can be a predictor for future risk of athero-thrombotic events. In this study pro-thrombotic activity was studied in smokers in form of platelet aggregability and serum C-reactive protein. Method: Platelet aggregability was measured by method given by O’Brien and C-reactive protein was measured by rapid latex agglutination test in male smokers consuming minimum 5 cigarettes per day for more than 3 years. Result: Platelet aggregability was found significantly increased in smokers. C-reactive protein levels were also found raised in smokers. Conclusion: Increased platelet aggregability in smokers could be due to endothelial injury and increased sympathetic activity. Increased C-reactive protein could be due to chronic inflammation in lungs and damage to endothelium.