The early and late results of bypass surgery in 124 patients with unresectable oesophageal cancer are reported. Patients were grouped according to the extent of disease: group A, tumour localized to the oesophagus where severe pulmonary disease contra-indicated oesophagectomy (n = 9); group B, tumour less than or equal to 10 cm in length with mediastinal invasion (n = 81); group C, tumour greater than 10 cm in length with mediastinal invasion and/or fixed malignant lymph nodes (n = 33). Extent of disease was not recorded in one patient. The operative mortality was 4 per cent but 9 other patients died in hospital (hospital mortality, 11 per cent). Mortality was increased in patients undergoing colon bypass and in those with a large tumour load but these differences failed to reach statistical significance. The most frequent complication was neck sepsis, secondary to leakage from the proximal end of the excluded oesophagus. Eighty-nine per cent of the survivors could eat a normal, unrestricted diet on discharge and eighty-two per cent of survivors had complete and lasting relief from dysphagia. Median survival after bypass was 5 months but survival was significantly improved by radiotherapy to the tumour (P less than 0.001). Gastric bypass with radiotherapy is indicated in patients with extra-oesophageal spread of malignancy and in patients with tumours localized to the oesophagus who are unfit for resection. Bypass surgery may be contra-indicated in patients with a primary tumour greater than 10 cm in length and/or fixed lymph node metastases because mortality is increased and survival after operation is short.