A total of 145 patients with early carcinoma of the vocal cords (T1,2N0) were treated by radiotherapy from 1979 to 1989. Survival and local control data were available for 135 and 127 patients, respectively. The respective 5 and 10 year results for overall survival were 75 and 68%. The 5 and 10 year probabilities of local control by radiotherapy were 89 and 86%, respectively, for T1 tumours and 70% at both time intervals for T2 tumours. Tumour recurrence following radiotherapy was documented in 18 of 127 patients. Tumour stage predicted significantly for local control, with recurrence rates for T1 and T2 tumours of 11 and 27%, respectively (P = 0.02). There was a higher proportion of recurrences for total radiation doses < or = 6200 cGy (17%) compared with > 6200 cGy (8%), but the difference was not statistically significant. Increasing duration of treatment was related significantly to increased recurrence for T2 (P = 0.01), but not T1, tumours. Most recurrences (60%) were salvaged successfully by laryngectomy. Three patients required laryngectomy for laryngeal oedema without recurrent tumour; all had been treated using a large field size (7 x 6 cm). There were 20 metachronous tumours, including five lung and two head and neck tumours. These results are similar to previous reports and confirm that radiotherapy is very effective for early glottic cancer, with high local control rates and effective salvage if local recurrences are recognized early.