Background: Barrett's oesophagus is a premalignant condition leading to adenocarcinoma. The incidence of adenocarcinoma of the oesophagus and the gastro‐oesophageal junction is rapidly increasing in the USA, northern and central Europe. Data from southern Europe are still unavailable. Objective: To evaluate the incidence of oesophageal adenocarcinoma in a large cohort of Italian patients with Barrett's oesophagus. Methods: A total of 344 patients (253 males and 91 females, age range 19‐75 years) with histologically proven Barrett's oesophagus (length of metaplasia ≥3cm) were enrolled from November 1987 to June 1995. Endoscopic and histological examinations were scheduled at yearly intervals. Results: One hundred and eighty‐seven patients complied with the follow‐up. The mean duration of the follow‐up period was 36 months (total follow‐up 562 patient‐years; range 12‐90 months). Low grade dysplasia was found in five patients at the initial examination. During the surveillance period, dysplasia increased in frequency as well as in severity and was found exclusively in the intestinal type of Barrett's oesophagus. In all, dysplastic changes were found in seven patients (five low grade and two high grade) and adenocarcinoma developed in three patients during the follow‐up. In a single case, both adenocarcinoma and specialized columnar epithelium developed without any evidence of dysplasia or intestinal metaplasia at the previous follow‐up examination. This prospective study shows an incidence of adenocarcinoma in Barrett's oesophagus of 1/187 patientyears. When only patients with specialized columnar epithelium were considered, the risk of adenocarcinoma was 1/88 patient‐years. Conclusion: The present report shows that the incidence of adenocarcinoma in Italian Barrett's oesophagus patients is in the range of that reported from other Western countries.