We prospectively determined the intraoperative blood loss in 250 patients who underwent major head and neck surgical procedures over a 13-month period to demonstrate the efficacy of electrosurgical dissection for reducing blood loss and to determine those factors predictive of the need for blood replacement. Transfusions were required in 30 (12%) of the 250 patients, and a total of 66 units of packed red blood cells was administered. Two patients were transfused preoperatively, 16 patients intraoperatively, and 14 patients postoperatively. Factors predicting the necessity for blood replacement included the patient's preoperative hematocrit level, intraoperative blood loss, the duration and type of procedure, and the surgeon's level of experience. The principles of electrosurgical dissection are discussed.