Pain following tonsillectomy is an important problem. It is caused by the surgical trauma of excision and haemostasis. Numerous surgical and pharmacological solutions have been tried, with disappointing results. Fibrin sealant is a widely used atraumatic haemostatic agent. This study aims to determine whether tonsillectomy with fibrin sealant haemostasis results in less post-operative pain than that with the conventional technique of diathermy. Fifty consecutive adult patients undergoing tonsillectomy were prospectively studied. They were randomized to receive either fibrin sealant or diathermy haemostasis. Other pain variables were controlled. Pain was measured by a visual linear analogue scale and inter-incisor distance on both the day of operation and the first post-operative day. The patients and pain measurer were blind to the randomization. The results showed that tonsillectomy with fibrin sealant haemostasis was significantly (P < 0.05) less painful than that with diathermy on both days studied and by both methods of pain measurement.