Objectives: The present study investigated the effectiveness of motivational interviewing in treating overweight and obesity among patients with coronary heart disease. Method: Using Quasi-experimental, pretest- posttest design with a control group, 110 patients who had previously coronary artery bypass grafting (CABG) were selected and assigned to two groups: experimental (n=60) and control (n=50) groups. These two groups had scored on body mass index (BMI) equal or above 25. The experimental group participated in motivational interviewing sessions in addition to regular cardiac rehabilitation programs. BMI, symptomatic depression, anxiety and stress were assessed in pretest and posttest (after three months). Data were analyzed using repeated measures analysis of variance regarding criteria of BMI for overweight and obesity. Results: Motivational interviewing was effective in controlling overweight, but not in the obese group. Conclusion: The findings indicate that motivational interviewing is effective to control overweight as a risk factor of coronary heart disease. Overweight is more related to lifestyle than obesity. It seems obesity is under influence of non-modifiable factors like genetic which is not easy to change.