In this paper we report our experience of routine symptom limited maximal treadmill assessment, and the methodology used with patients at the end of their convalescence after myocardial infarction. Sixty-one of 68 (90 percent) consecutive patients, mean age 55.7 years (21 to 69 years), were studied at the median time after infarction of six weeks (three to 16 weeks). No complications occurred during or after the tests. Fifty-six percent of the patients studied achieved a work capacity which was within the average range reported for healthy people of the smae age. Thirty-two percent experienced chest pain thought to be angina and 31 percent developed ST segment depression of at least 1 mm without chest pain. Although ventricular premature beats occurred in half the tests the only arrhythmia requiring any treatment was a supraventricular tachycardia. The assessment of work capacity and limiting symptoms in this way after myocardial infarction is safe and is of considerable help in patient management.