Polycythemia vera is a myeloproliferative disorder predisposing to thromboembolic and bleeding complications. We report the case of a patient with polyglobuly, leukocytosis, and thrombocytosis, who suffered from acute ST-segment elevation myocardial infarction due to thrombotic high-grade pre-stent stenosis two months after percutaneous coronary intervention for complex coronary one vessel disease. Following re-PTCA and stent implantation in conjunction with periinterventional GP IIb/IIIa antagonist treatment, the patient was initially symptom free for about two hours before rapidly developing signs of a hemorrhagic shock. An abdominal CT scan showed splenic rupture with massive intraabdominal hemorrhage as a consequence of secondary bleeding into multiple pre-existing splenic infarctions. The patient's condition stabilized after emergency splenectomy. Subsequent bone marrow biopsy revealed the presence of polycythemia vera. Post-operatively, the patient was treated with the anti-platelet agents aspirin and clopidogrel to prevent subacute stent thrombosis. Additionally, cyto-reductive therapy with hydroxyurea was initiated because of a further increase in the platelet count. In patients with polycythemia vera, the indication for treatment with GP IIb/IIIa antagonists should be carefully weighed against the potentially serious bleeding complications. Should treatment be established, a risk stratification using abdominal sonography and bleeding time testing is recommended, while during treatment red blood count, platelet count, coagulation tests, and hemodynamic parameters should be closely monitored.