The objective of this study was to assess the use of blood products and artificial colloids in six commonly performed elective surgical procedures in 43 teaching hospitals in 10 European countries. 7,195 patient data were analysed. For each product wide differences were found between hospitals, both in the proportion of patients transfused and the amount of product used for the same patient category. Adjustment for age, gender, preoperative haematocrit and blood loss, left major differences among hospitals in patient red unit transfusion. Hospitals in the Mediterranean area used less albumin and artificial colloids and more autotransfusion than those of central-northern Europe. The reasons for perioperative red cell transfusion were stated in the patient's medical record for 23% of patients. The ratio of preoperative blood request to transfusion was maximal in cholecystectomy, where it exceeded 10. The documentation of blood request and transfusion, and of transfusion complications in medical records, did not fully agree with that in the transfusion service in 49, 53 and 92% of the hospitals, respectively. The wide differences in blood product used for the same patient category were due to a variety of causes of which only some could be explained by the clinical factors taken into account. This suggests that consensus conferences and guidelines have so far had a limited impact on transfusion practice in many clinical units, even in teaching environments.