The main cause of haemostasis defects and related bleeding complications in patients with acute coronary syndromes admitted to the intensive cardiac care unit is the use of multiple antithrombotic drugs, alone or concomitantly with invasive procedures such as percutaneous coronary intervention with stent deployment and coronary artery bypass surgery. These drugs, that act upon several components of haemostasis (platelet function, coagulation, fibrinolysis), are associated with bleeding complications, particularly in elderly patients (more so in women than in men), those who are underweight, and those with comorbid conditions such as renal and liver insufficiency and diabetes. The identification of patients at higher risk of bleeding is the most important preventive strategy. Red cell and platelet transfusions, which may become necessary in patients with severe bleeding, should be used with caution, because transfused patients with acute coronary syndrome have a high rate of adverse outcomes (death, myocardial infarction, and stroke). To reduce the need of transfusion, haemostatic agents that decrease blood loss and transfusion requirements (antifibrinolytic amino acids, plasmatic prothrombin complex concentrates, recombinant factor VIIa) may be considered. However, the efficacy of these agents in the control of bleeding complications in acute coronary syndrome is not unequivocally established, and there is concern for an increased risk of re-thrombosis. A low platelet count is another cause of bleeding in the intensive cardiac care unit. The main aetiologies are drugs (unfractionated heparin and glycoprotein IIb/IIIa inhibitors), thrombotic microangiopathies, such as thrombotic thrombocytopenic purpura, and disseminated intravascular coagulation, that are often paradoxically associated with thrombotic manifestations. In conclusion, evidence-based recommendations for the management of bleeding in patients admitted to the intensive cardiac care unit are lacking. Accurate assessments of the risk of bleeding in the individual and prevention measures are the most valid strategies.