A clinico-pathological study was carried out in two series of patients in order to determine: the prevalence of adenocarcinoma in Barrett's oesophagus in patients undergoing surgical resection for columnar cancer of the oesophagus, the incidence of Barrett's oesophagus in patients with complications of gastro-oesophageal reflux, and the subsequent cancer development in 3-20 years follow-up of such patients, compared with others who had no Barrett's oesophagus. Group 1 consisted of 264 patients with adenocarcinoma of the oesophagus undergoing resection and reconstruction; 18 (6.8%) had concomitant carcinoma and Barrett's oesophagus. These were predominantly male (male/female ratio 8/1) and had worse long-term survival than the other adenocarcinomas. Group 2 consisted of 782 patients with complications of gastro-oesophageal reflux, 26 (3.3%) of whom were found to have Barrett's oesophagus. When followed up for a period of up to 20 years, 4 (15.4%) of these developed cancer in the mean period of 11.5 years (1 case per 74 person-years). This is highly significant compared with 4 others (0.5%) who developed cancer amongst the 756 remaining patients in group 2 with no Barrett's oesophagus, in the mean interval of 8 years 2 months (1 case per over 1500 person-years). Of the 18 patients with Barrett's stricture, 4 (22%) developed cancer at a mean interval of 11.5 years representing one case per 51.7 person-years indicating a higher risk of cancer development in patients with Barrett's stricture compared with other patients with complications of gastro-oesophageal reflux with/without columnar epithelial-lined oesophagus and no stricture. Anti-reflux operation has not protected our patients with Barrett's oesophagus against cancer development.