Primary dissecting aneurysm of a coronary artery is a rare form of acute coronary arterial obstruction.A review of 24 cases, including two observed by the authors, indicates that this condition tends to occur (1) in the young adult, (2) in the female more commonly than the male, and (3) relatively commonly in the postpartum state.The clinical manifestations take the form either of sudden death or acute myocardial infarction. In the latter situation, there is the potential for overcoming the coronary arterial obstruction by a surgical bypass procedure.