This study examined the effects of a self-efficacy enhancement program for the cardiac rehabilitation of Thai patients who had a myocardial infarction. Sixty-six hospitalized patients of various ages and both genders were randomly assigned to either an experimental or a control group. Participants in the experimental group took part in three individualized in-hospital education sessions and three weekly sessions of telephone counseling. The control group primarily engaged in a supervised exercise and activities of a daily living performance regimen, and received education in this regard. Self-efficacy and functional status were measured via questionnaire. Four weeks after discharge, the experimental group was found to have significantly higher total self-efficacy and functional status scores than the control group. In addition, the experimental group exhibited significantly higher subscale scores on social activity, household tasks, occupation, and exercise self-efficacy than the control group. These results indicate that the program is effective in improving the self-efficacy and functional status of Thai patients who have had a myocardial infarction.