The incidence of gallstone development after selective hepatic vagotomy was evaluated in a prospective study, comparing it with a control group. There were 26 subjects with normal gallbladder, who were studied 3 to 5 years later and compared with 22 patients with reflux esophagitis who were operated and followed in a similar way. In all patients a selective hepatic vagotomy was performed as part of the posterior gastropexy. All had oral cholecystograms before and after surgery. In normal subjects 2 of the 26 cases (7.7%) and in the operated patients 9 of the 22 (41%), showed gallstones during the second evaluation. This incidence is statistically different. The importance of this finding is discussed.