There are no published guidelines for the use of red cells, platelets and fresh frozen plasma (FFP) in critically ill patients. This study aimed to examine the attitudes of intensivists and haematologists to the use of blood and blood products. A scenario based postal questionnaire used previously to elicit transfusion practices of Canadian critical care physicians1 was modified to assess current practice of red cell, platelet and FFP use in intensive care. Four hypothetical scenarios: trauma (1), sepsis (2), pneumonia (3) and acute bleeding (4) were described. Each scenario had a series of clinical situations commonly seen in critically ill patients. The questionnaire was circulated to the directors of intensive care units and haematologists in charge of blood banks in all hospitals in England. Data were analysed using Wilcoxon matched-pairs test, Friedman two-way ANOVA and Mann–Whitney U test. A total of 162 intensivists and 77 haematologists responded. Baseline transfusion thresholds for red cells ranged from 6 to 12 g dl−1. There was significant (P<0.005) interscenario variations. Increasing age, high APACHE score, surgery, ARDS, septic shock and lactic acidosis significantly (P<0.005) modified the threshold. There were greater variations in the baseline threshold for platelet transfusion. A total of 21.5% selected a threshold of <30×109 litre−1. Surgery and invasive procedures significantly (P<0.005) altered the threshold. Baseline threshold Prothrombin time (PT) for transfusion of FFP ranged from 1 to >2.5 times control. Bleeding significantly (P<0.01) lowered the threshold. The majority of respondents (72.3%) selected a baseline Hb threshold of 9–10 g dl−1 (Table 19). The thresholds for platelets and FFP were far less consistent.