To evaluate the clinical features, complication rates, and mortality from infarction in the coronary care unit, we analysed all cases of acute myocardial infarction admitted to the Coronary Care Unit of the Singapore General Hospital over a 4 month period in 1988. There were 184 cases of acute infarction with a male:female ratio of 3.4:1. Fifty-five percent of patients were aged 60 years or above. Complications included congestive cardiac failure in 40%, sustained ventricular tachycardia in 9%, cardiogenic shock in 18% and complete heart block in 8%. The overall in-hospital mortality was 20.6%. Multiple logistic regression analysis of clinical variables showed that of the clinical variables, age (elderly patients) and the diabetes were independently associated with a higher mortality as well as development of cardiogenic shock and sustained ventricular tachycardia. Comparing our results with previous smaller studies of CCU outcome in 1975 and 1967, there was a marked increase in the proportion of elderly patients in 1988 but despite this the overall mortality rate was not significantly different. Age is the most important clinical variable predicting outcome from infarction.