OBJECTIVE: To evaluate efficiency and postoperative morbidity in tonsillectomy using the harmonic scalpel (HS) vs conventional electrocautery (EC). DESIGN: A retrospective medical chart review of all patients who underwent tonsillectomy at a single children's hospital during a 32-month period from January 2001 to August 2003. PATIENTS: The charts of 605 patients who underwent tonsillectomy or adenotonsillectomy were reviewed. The patients were stratified into 2 groups based on the dissecting instrument used (HS vs EC). Each group consisted of 2 subcategories based on age (< or =7 years and >7 years). Data collected included age, sex, operative indication, operative time, postanesthetic recovery room time, pain scale scores, postoperative admissions, and postoperative morbidities. RESULTS: There were significant differences in mean age (P<.001), mean weight (P<.001), and indication for surgery (P<.001) between the 2 methods: HS patients were younger, weighed less, and more often had obstructive symptoms as their primary operative indication compared with the EC group. Average operative times were not significantly different between methods. No differences were noted with respect to recovery time (HS group, P = .10; EC group, P = .30), postoperative oxygen requirements (HS group, P = .07; EC group, P = .09), and postoperative pain scores (HS group, P = .31; EC group, P = .58). There was a significant difference in postoperative admissions between the 2 methods in patients 7 years or younger (P = .005). Finally, we noted a significant difference in postoperative bleeding between the HS (2/292) and EC (13/313) methods when the data were compared per age group (P = .006), but the overall bleeding rate was not statistically significant owing to the small number of total bleeding instances (15/605). CONCLUSIONS: Recent prospective studies indicate that the HS provides advantages over conventional EC with respect to postoperative pain and return to normal activity. This study shows that HS tonsillectomy was as efficient as the conventional EC method. In addition, there was evidence that the rate of postoperative bleeding was significantly reduced by using the HS vs conventional EC.