Hypothetical clinical cases were used to investigate transfusion-related decision-making. Three red cell, three fresh frozen plasma (FFP) and three albumin transfusion decision cases were administered by questionnaire to 228 medical staff. The transfusion decision triggers were identified and comparisons made between resident and specialist groups and between Melbourne and Sydney participants. Factors important in red cell transfusion decisions included haemoglobin, symptoms of anaemia, presence of co-morbidities or surgery, gender, period of hospitalisation and the degree of documented blood loss. FFP administration was influenced by an abnormal coagulation test, the presence of co-morbidities and by the number of red cell units transfused. The administration of albumin, concentrated or 5% SPPS, was influenced by the period of hospitalisation and clinical circumstances such as a falling urine output postoperatively, and by the presence of hypotensive complications. Different transfusion responses were noted: resident staff transfused red cells and FFP earlier than specialists; Sydney specialists were more conservative of red cell transfusion; Melbourne specialists more conservative of FFP administration and surgeons were four times more likely to transfuse patients than physicians or anesthetists at certain haemoglobin values.