Regression of Barrett's epithelium after antireflux operations remains a controversial topic. We evaluated the effect of antireflux procedures in patients with Barrett's esophagus on the regression of columnar epithelium and dysplasia and its potential protective effect on the subsequent development of carcinoma. Of the 241 patients with Barrett's esophagus treated at the Lahey Clinic from 1973 to 1989, 37 patients underwent an antireflux operation. Regression was defined as histological evidence of regenerating squamous mucosa that completely or partially replaced the columnar epithelium. Improvement in lower esophageal sphincter pressure to 12 mm Hg or greater occurred in 19 of 26 patients (73%) who had perioperative manometry. Symptomatic relief of esophagitis occurred in 34 of 37 patients (92%). Four patients had partial regression with regenerating squamous mucosa juxtaposed with areas of columnar epithelium. Carcinoma developed in 3 of 37 patients (8.1%). One patient had recurrence of severe symptoms of reflux esophagitis before development of carcinoma. Patients with Barrett's esophagus who have undergone a successful antireflux operation with symptomatic relief and evidence of improvement in lower esophageal sphincter pressures rarely show regression of Barrett's mucosa and may still be at risk for development of carcinoma. Therefore, the indications for antireflux operation in Barrett's esophagus should remain the same as for other patients with gastroesophageal reflux, but yearly endoscopic and histological surveillance should be continued postoperatively.