Desmopressin (DDAVP) has been reported to reduce bleeding in patients undergoing spinal fusion. To evaluate its efficacy in normal patients, 30 healthy young patients (ASA physical status I or II) undergoing spinal fusion for idiopathic scoliosis were randomly allocated to receive either 100 mL of physiologic saline solution (placebo group) or DDAVP (10 micrograms/m2 of body surface area) (DDAVP group) in a prospective, double-blind trial. Intraoperative blood loss was measured by weighing sponges and suction drainage and postoperative bleeding by wound drainage. The amount of blood loss expressed as a percent of the estimated blood volume was similar in both groups during the intraoperative period (67.0% +/- 28.8% [mean +/- SD] placebo group vs 57.4% +/- 26.5% DDAVP group), the postoperative period up to 24 h (32.5% +/- 6.4% placebo group vs 31.1% +/- 10.6% DDAVP group), and both periods (94.3% +/- 29.4% placebo group vs 88.2% +/- 30.7% DDAVP group). With the dose used in our study, we conclude that DDAVP does not reduce surgical bleeding in patients undergoing spinal fusion for idiopathic scoliosis.