A prognostic index for patients with acute myocardial infarction treated in a coronary care unit was presented. It was derived by multiple regression analysis, and was based on the only three factors, of the many examined, that made significant independent contributions to the outcome. These were the serum aspartic aminotransferase (SGOT) level, cardiogenic shock, and oliguria. The system of scoring was simple, especially with a readyreckoner which was provided. There was very good agreement between the coronary prognostic index and the observed mortality rate, and there was a highly significant linear correlation between the two (r=oo986,