Objectives: The present research was carried out to investigate the role of psychological structures particularly dysfunctional attitudes with its consequence depression in incidence and severity of coronary heart disease. Method: In this research 30 patients (28 males and 2 females) suffering from myocardial infarction and 30 nonpatient individuals (28 males and 2 females) after matching were studied and compared with regard to depression and dysfunctional attitudes through Beck Depression Inventory, Dysfunctional Attitudes Scale and Personal Data Questionnaire. In addition, severity of myocardial infarction in relation to depression and dysfunctional attitudes in patient group was also studied. Research data were analyzed through t-test and coefficient of correlation. Results: This investigation indicated that frequency of depression in patients suffering from myocardial infarction is more than nonpatient group and the mean of their severity of depression as compared to nonpatinet group is significant. Also, the mean score of dysfunctional attitudes in patient group as compared to nonpatient group has a significant difference. Although in both the groups there is a positive correlation between depression and dysfunctional attitudes, but this correlation is much stronger in patient group than in nonpatient group.