Depression has been reported to be common in patients with coronary artery disease (CAD), using a variety of criteria for the diagnosis of depression. However, many studies have relied solely on the presence of symptoms such as a dysphoric mood and fatigue in making a diagnosis of depression. Both fatigue and dysphoric mood are also associated with medical illnesses, and psychiatric diagnoses based on such nonspecific symptoms may lack the specificity necessary to predict the need for psychiatric treatment. To assess the incidence of depression likely to require and respond to psychiatric treatment, 50 patients documented to have CAD by coronary angiography underwent psychiatric diagnostic interviews. Current research-based criteria (DSM-III) were used to make diagnoses of major depressive disorder. In addition, the applicability of a brief screening inventory the (Beck depression inventory) for detecting the presence of depression in these patients was tested. Nine patients (18%) met criteria (DSM-III) for major depressive episode. Depression was not related to the extent of CAD, age or use of beta blockers. There was a relation between depression and smoking. Only 2 of the 9 depressed patients had been diagnosed previously and were being treated for depression. When a score of greater than or equal to 10 on the Beck depression inventory was used to distinguish patients with depression, it had moderate sensitivity (78%) and specificity (90%) for the identification of depression.