Aggressive risk factor modification decreases cardiovascular events and mortality in patients after coronary artery bypass grafting (CABG). Little is known regarding the use of secondary prevention in older patients undergoing CABG during hospitalization for acute myocardial infarction (AMI). Medical records were reviewed for a sample of 37,513 patients hospitalized with AMI in the United States between April 1998 and March 1999. Patients >or=65 years of age who underwent CABG after AMI (n=2,267 [8%]) were evaluated for the prescription of 4 therapies at discharge: aspirin, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and lipid lowering, in eligible patients without contraindications to therapy and compared with patients who did not undergo CABG (n=26,484 [92%]). Patients undergoing CABG had higher rates of aspirin than patients who did not undergo CABG (88.0% versus 83.2%, P=0.0002). However, CABG patients were less likely to receive beta-blockers (61.5% versus 72.1%, P<0.0001), ACE inhibitors (55.5% versus 72.1%, P<0.0001), or lipid lowering (34.7% versus 55.7%, P<0.0001) prescriptions than patients who did not undergo CABG. After adjustment for disease severity, patients undergoing CABG were no longer more likely to receive discharge aspirin, and the magnitude of other differences in care increased. Evidence-based discharge therapies are underutilized in older patients who underwent CABG during hospitalization for AMI. Although national efforts focusing on improving short-term surgical mortality have been successful, strategies should be developed to increase the utilization of therapies known to improve long-term mortality in patients undergoing CABG.