We surveyed contemporary Australasian cardiac surgical and anaesthetic practice, focusing on antiplatelet and antifibrinolytic therapies and blood transfusion practices. The cohort included 499 sequential adult cardiac surgical patients in 12 Australasian teaching hospitals. A total of 282 (57%) patients received red cell or component transfusion. The median (IQR) red cell transfusion threshold haemogloblin levels were 66 (61-73) g/l intraoperatively and 79 (74-85) g/l postoperatively. Many (40%) patients had aspirin within five days of surgery but this was not associated with blood loss or transfusion; 15% had clopidogrel within seven days of surgery. In all, 30 patients (6%) required surgical re-exploration for bleeding. Factors associated with transfusion and excessive bleeding include pre-existing renal impairment, preoperative clopidogrel therapy, and complex or emergency surgery. Despite frequent (67%) use of antifibrinolytic therapy, there was a marked variability in red cell transfusion rates between centres (range 17 to 79%, P < 0.001). This suggests opportunities for improvement in implementation of guidelines and effective blood-sparing interventions. Many patients presenting for surgery receive antiplatelet and/or antifibrinolytic therapy, yet the subsequent benefits and risks remain unclear.