The aim of this study was to assess the effect of surgery on normal tissue toxicity in head and neck cancer patients treated with accelerated radiotherapy. Toxicity data from two trials of accelerated radiotherapy were compared. The first group was taken from a phase III trial of definitive radiotherapy and the second group from a phase II trial of postoperative radiotherapy. The general eligibility criteria (apart from surgery), data collection and radiotherapy details for both trials were similar. The definitive group included 172 eligible patients and the postoperative group 52 eligible patients. At 3 weeks into treatment, by which time the dose and rate of dose accumulation were identical, there was no difference in acute toxicity. Analysis of late toxicity showed greater subcutaneous fibrosis in the postoperative group.