The key role of platelets in the pathogenesis of ischemic heart disease has led to the development of new classes of agents to control platelet function. The platelet glycoprotein IIb/IIIa receptor mediates the final common pathway to platelet aggregation. Drugs that block the glycoprotein IIb/IIIa receptor potently inhibit platelet aggregation. Monoclonal antibodies, cyclic peptides, and peptide-derivative glycoprotein IIb/IIIa inhibitors have been developed. The monoclonal antibody Fab fragment, chimeric 7E3, has been shown to significantly reduce ischemic complications and clinical restenosis after high-risk angioplasty in the large-scale Evaluation of 7E3 for the Prevention of Ischemic Complications (EPIC) trial. A number of glycoprotein IIb/IIIa inhibitors have been tested in patients with unstable angina with similarly positive results, and initial trials in patients with acute myocardial infarction are also encouraging. Further evaluation of these agents in large scale trials is currently underway and should help determine the place and appropriate use of these agents in the clinical arena.