Abnormal origin of the coronary arteries from the pulmonary artery can occur in four different ways. Either the left or the right coronary artery, both coronary arteries, or an accessory coronary artery may arise from the pulmonary artery. The most frequent of these malformations is the abnormal origin of the left coronary artery. Many publications have dealt with the clinical, physiological, and anatomical picture of this malformation (7). The majority of patients are symptomatic in early life because of marked anoxia of the anterolateral and apical portions of the left ventricle, the result of insufficient intercoronary anastomoses. Some patients, however, may become symptomatic later in life, and in these abundant anastomoses are found between both coronary arteries. From catheterization and angiographic investigations, there is conclusive evidence that the blood flow is directed from the right coronary artery through intercoronary anastomoses into the distal branches of the left coronary artery and from there in retrograde fashion into the pulmonary artery (1, 7, 13, 16). The other three forms of abnormal origin of the coronary artery from the pulmonary artery are extremely rare. An accessory coronary artery arising from the pulmonary artery has been described in only a few cases and represents an incidental finding (8). Origin of both coronary arteries from the pulmonary artery is not compatible with life, and infants with such a malformation die within the first two weeks after birth (19). The origin of the right coronary artery from the pulmonary artery has been described by several authors (2–4, 9, 14, 15, 17) . No publication of such a malformation diagnosed clinically could be found, and the following observation is reported. A Negro girl of six and a half years was admitted to The University of Chicago, with moderate cyanosis and clubbing of fingers and toes apparent on physical examination. A mild right ventricular tap was palpable and barely visible. A grade 4/6 harsh systolic murmur, starting after S1 and ending distinctly before S1, was heard best along the lower left sternal border, radiating faintly to the apex and the left back, but was well audible along the upper left sternal border. A grade 2/6 soft diastolic murmur (early mid-diastolic but not proto-diastolic) was present at the apex, as well as at the anterior axillary line in the fifth intercostal space. In conjunction with the systolic murmur, this one had a distinct to-andfro character, the diastolic component being louder than the (? transmitted) systolic component. No other murmurs were discovered. The remainder of the physical examination was within normal limits. Laboratory Data With the exception of a hematocrit of 48 per cent and a hemoglobin of 14.7 g per 100 cc, this patient's blood count, blood electrolytes, blood-urea-nitrogen, clotting and bleeding time, as well as findings on urinalysis, were within normal limits.