BACKGROUND Coronary angiography is indicated for many patients after acute myocardial infarction (AMI). There are a number of subgroups of AMI patients, however, for whom the indication for coronary angiography is not well established. RESULTS We developed a decision-analytic model for AMI in representative patient subgroups based on relevant clinical characteristics. The model estimates quality-adjusted life expectancy and direct lifetime costs for two strategies: coronary angiography and treatment guided by its results versus initial medical therapy without angiography. Decision tree chance node probabilities were estimated with the use of pooled data from randomized clinical trials and other relevant literature, costs were estimated with the use of the Medicare Part A database, and quality of life adjustments were derived from a survey of 1051 patients who had had a recent AMI. In our analysis, incremental cost-effectiveness ratios for coronary angiography and treatment guided by its result, compared with initial medical therapy without angiography, ranged between $17,000 and > $1 million per quality-adjusted year of life gained. Patient subgroups with severe postinfarction angina or a strongly positive exercise tolerance test (ETT) typically had cost-effectiveness ratios of < $50,000 per quality-adjusted year of life gained. In addition, most patient subgroups with a prior AMI had cost-effectiveness ratios of < $50,000 per quality-adjusted year of life gained, even with a negative ETT result. CONCLUSIONS In many patient subgroups after AMI, the cost-effectiveness of routine coronary angiography and treatment guided by its results compares favorably with other treatment strategies for coronary heart disease.