Antagonists of the glycoprotein IIb/IIIa receptor block the binding of fibrinogen and Von Willebrand factor to the platelet receptor. This effect can lead to bleeding and thrombocytopenia. We analyzed the incidence and clinical repercussions of severe thrombocytopenia (< 20 000 /microl) secondary to abciximab treatment in a prospective study of 375 patients (74% men) who underwent percutaneous coronary revascularization and received abciximab at our hospital. We recorded clinical and demographic characteristics, angiographic findings, laboratory results and platelet counts (before, 4 hours after and 12 hours after the procedure) and hematocrit. The incidence of severe acute thrombocytopenia was 1.1%. All patients were men, and none had relevant bleeding complications. Management consisted of monitoring the bleeding, discontinuing the drug and transfusing platelets. Clinicians should be alert to this complication during the initial hours after the administration of abciximab.