BACKGROUND Patients undergoing surgery are an important user of red blood cells (RBC). Increasingly, medical staff and patients wish to know the likelihood of RBC transfusion for appropriate resource allocation and to inform preoperative discussions regarding risk. Although some adult data are available, little is known about RBC use in children. AIM The aim of this study was to describe RBC use in the perioperative period in a large pediatric hospital. METHODS Over a 2-year period the hospital operating theatre database and trauma registry was merged with the blood bank database to identify episodes where RBC units were transfused in association with anesthesia. Incidence of transfusion of RBC units associated with particular procedures was then calculated. RESULTS A total of 21 441 patients underwent 32 511 anesthetics from January 1, 2006 to December 31, 2007, and 9838 units of RBC were released from the hospital blood bank of which 4070 (41%) were transfused in the perioperative period. Cardiac surgery was the greatest user of RBC units (2359 units). Acute major trauma accounted for only 159 units. Overall 6.3% of anesthetics were associated with a RBC transfusion. The procedures with the greatest frequency of RBC transfusion were cardiac surgery on bypass (79%), cardiac off bypass (55%), liver transplant (87%) and cranioplasty (61%). CONCLUSION In a tertiary pediatric hospital surgery accounts for a substantial proportion of total RBC use, with particular procedures accounting for the majority of transfusions.