The study is comparitive study of ECG changes with special referance to QTC in smokers and non smokers. The subjects were those who were attending King George Hospital & Andhra Medical college at Visakhapatnam, Andhra Pradesh. Total number of subjects are 193 among which 103 are smokers and 90 are non smokers. Patients who are alchoholics and those with Diabetes, Hyper-tension and Coronary artery disease were excluded. A 12 lead Electrocardiogram was recorded for all the individuals. ECG changes and QTc was compared between smokers and non smokers. There is no statistically significant Change in QTc in smokers when compared to non smokers in the present study.