Background: Little IS known about predictors of lifestyle modification in overweight or obese patients with acute myocardial infarctions. Methods: Between October 2005 and May 2007, 311 overweight or obese patients with an AMI visited Kyungpook National University Hospital. Among them, 216 patients ($63{pm}11$ years old, 144 males) with ${geq}1$ year of follow-up were included. Results: Body weight of all patients showed a significant decrease and 20% showed a >3% weight reduction at 1 year of follow-up. Ninety-six (44%) patients were smoking at baseline, and 52% of them had quit by 1 year of follow-up. Only six smokers were successful with both a >3% weight reduction and smoking cessation. In multivariate analysis, age (OR 1.084, 95% CI 1.028-1.144, p=0.003) and smoking cessation (OR 0.167, 95% CI 0.048-0.575, p=0.005) were independent predictors of weight reduction. Abdominal circumference was a negative predictor of smoking cessation (OR 0.903, 95% CI 0.820-0.994, p=0.037). Conclusions: Mean body weight of all patients showed a significant decrease at follow-up. Smoking cessation and age were independent predictors of weight reduction, and abdominal circumference was a negative predictor of smoking cessation.