The hospital mortality was evaluated for 21 days in all patients with a first attack of acute myocardial infarction (AMI) in Israel. Total mortality was 21.1 percent. The following factors were associated with relatively better prognoses: age, young; sex, male; marital status, married; ethnic origin, European; site, subendocardial; history of smoking, and, to a certain degree, hypertension; low levels of white blood cells, blood sugar, serum transaminase and cholesterol; and anticoagulant therapy.