BACKGROUND AND PURPOSE: This report presents long-term follow-up data from a prospective but unrandomized trial of a continuous 3.5-week course of accelerated radiation treatment (ART) used as primary treatment for patients with loco-regionally advanced head and neck cancer. MATERIALS AND METHODS: Ninety-three patients in three centres in New Zealand and Australia were treated with ART (59.40 Gy in 33 fractions over 24-25 days). Their disease originated from three anatomical regions (oral cavity, 35 patients; pharynx, 31 patients; larynx, 27 patients). Seventy-nine of these patients had stage III or IV cancers. RESULTS: Follow-up ranged from 68 to 203 months (median 139 months). Loco-regional (LR) failure occurred in 52 patients leading to a 10-year actuarial expectation of LR control of 38%. The actuarial expectation of LR control at 10 years was highly dependent on stage and for stage III, IVA and IVB patients it was 57+/-8.1%, 32+/-1.7% and 7+/-0.5%, respectively. Multivariate analysis could not confirm an independent impact of primary site or histological differentiation on LR failure. Two patients died of acute toxicity of treatment and six patients developed grade 3/4 late complications affecting soft tissues only, yielding an actuarial expectation of complications of this severity at 5 years of 9%. No cases of osteoradionecrosis or myelitis were observed. CONCLUSION: This ART, which has proved easy to use at a number of large and small centres, has produced encouraging long-term LR control at a cost of limited soft tissue morbidity.