Two hundred eighty-three patients admitted to cardiac care units for myocardial infarction at two urban teaching hospitals were interviewed 8 to 10 days after infarction and 171 were reinterviewed 3 to 4 months later. Initially, 45% met diagnostic criteria for minor or major depression, including 18% with major depressive syndromes. Depression was not associated with the severity of cardiac illness but was associated with the presence of noncardiac medical illnesses. Three to 4 months after infarction, 33% of patients met criteria for minor or major depression. The large majority of patients who initially met criteria for major but not minor depression showed evidence of depression at 3 months and most patients with major depression had not returned to work by 3 months. Treatment of major depressive syndromes after myocardial infarction may reduce chronicity and disability, while minor depressive syndromes may be similar to normal grief and tend to be self-limited.