In 1987 we established an Italian multicenter study involving 16 gastroenterologic institutions. The main aims of the study were to assess the prevalence of Barrett's esophagus in a cohort of patients undergoing upper gastrointestinal endoscopy, and the relationship between endoscopic and histologic features. We enrolled 14,898 consecutive patients, and found 251 (1.7%) had endoscopic findings consistent with Barrett's esophagus and/or esophagitis (grade 2 to 4 according to Savary). On histological examination, Barrett's esophagus was confirmed in 111 of 251 patients (44.2%). The crude prevalence rate of BE, based on histology, was 7.4/1,000, and was 2.6-fold higher in males than in females (c.i. 1.7-4.0). Barrett's esophagus proved to be 25-fold more frequent among patients who complained of heartburn (80.1/1,000) than among the others (3.2/1,000). Specialized columnar epithelium was identified in 69 of 111 cases (62.2%) and the proportionate distribution of the histological subtypes was similar in males and in females (chi-square Idf = 0.20, p = n.s.). Dysplasia was detected in 7 patients, all of whom had specialized columnar epithelium (6 low grade and 1 high grade). In conclusion, we believe that our rate of 7.4/1,000 approaches the true prevalence rate of Barrett's esophagus, as it is based on our study of unselected patients presenting for initial evaluation of a variety of UGI symptoms. The occurrence of dysplasia in specialized columnar epithelium suggests that patients with this subtype of Barrett's esophagus may be at increased risk for developing cancer and might, therefore, benefit most from surveillance.