A study of patients with cardiac infarction, treated in hospital between 1950 and 1954 and followed up to the present, is reported. One hundred and forty-two patients suffered 169 attacks. In 95 attacks, the patients received anticoagulant therapy, with 15 acute deaths. Fifty-six were not so treated; among these there were 21 deaths. The rate of survival was best in younger patients with their first episode of infarction, without preexisting hypertension, cardiac failure, or systolic blood pressure persistently below 100. Angina preceding infarction disappeared in one-half of the subjects after the episode; half the survivors suffered recurrent myocardial infarction within five years. Moderate hypertension had no effect upon immediate or 10-year survival. No patient received long-term anticoagulant therapy. Of the survivors of acute infarction, 16 died in the first year after the acute attack, nine in the second year, nine in the third, six in the fourth and five in the fifth. At the end of five years, 51 subjects had survived 60 episodes. At the end of 10 years, 43 living patients had sustained 45 myocardial infarctions.