We examined differences in the use of invasive diagnostic and therapeutic coronary procedures between white and black Medicare beneficiaries following acute myocardial infarction. We used Medicare hospitalization data for patients aged 65 years or older who were hospitalized with an acute myocardial infarction in 1988, and we followed them through the calendar year to determine whether they received invasive coronary procedures. We used multivariate logistic regression to control simultaneously for multiple potential confounding factors including age, geographic region, poverty, comorbid conditions, access to hospitals equipped to provide invasive procedures, and short-term survival. We calculated odds ratios for racial differences in use of invasive diagnostic procedures (coronary arteriography, cardiac catheterization) and, separately, of myocardial revascularization procedures (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty). We found that the odds of receiving an invasive diagnostic procedure after acute myocardial infarction were 2.0 times greater for white men than for black men (95% CI: 1.8-2.1); for white women, the odds were 1.5 times greater than for black women (95% CI: 1.4-1.6). Following an invasive diagnostic procedure, the odds of myocardial revascularization were 1.8 times greater among white than among black men (95% CI: 1.6-2.0), and 1.7 times greater among white than among black women (95% CI: 1.6-2.0). We conclude that invasive diagnostic and therapeutic coronary procedures are used more often among white than among black Medicare beneficiaries following acute myocardial infarction. Further investigation of this discrepancy will require detailed clinical and attitudinal information from medical records, patients, and physicians.