Platelet activation plays a major role in the pathophysiology of acute coronary syndromes (ACS), and inhibition of platelet function is the basic pharmacological treatment of ACS. Platelet membrane glycoprotein IIb/IIIa inhibitors, a new class of potent antiplatelet agents, have been used in the treatment of ACS, as well as in the prevention of complications after percutaneous coronary interventions. The aim of this article is to describe the potential possibilities of platelet inhibition and to review the pharmacology of glycoprotein IIb/IIIa inhibitors, the results of the clinical trials with these agents, and their current use in the pharmacological treatment of ACS and in relation to percutaneous coronary intervention.