Thirty-two patients participated in a study to compare the use of an ultrasonically activated scalpel (Harmonic scalpel) for tonsillectomy on one side and a blunt dissection tonsillectomy on the other. Pain scores at rest and on swallowing expressed as the area under curves (AUC) during the 10 h after surgery, intra-operative blood loss and the need for electrocoagulation for haemostasis were significantly higher on the blunt dissection side than on the Harmonic scalpel side (p < 0.05). However, pain scores expressed as AUC at rest, on swallowing, the day's least, average and worst levels of pain, and the day's worst otalgia during the second week after surgery were significantly higher on the Harmonic scalpel side than on the blunt dissection side. In conclusion, we found that Harmonic scalpel tonsillectomy was associated with decreased severity in pharyngeal pain on the day of the operation but increased pharyngeal pain and otalgia during the second postoperative week.