A simple competency test has been devised that will establish the adequacy of a Nissen fundoplication at the operating table. Saline, 250 ml, is instilled into the stomach through a nasogastric tube and then the nasogastric tube is withdrawn to above the level of plication. The pylorus is occluded and the stomach compressed. If the cardia is competent, no saline can be aspirated from the esophagus. Ten patients studied immediately after the opening of the abdomen showed regurgitation by this test, whereas no regurgitation could be produced in 30 patients studied immediately after completion of the fundoplication.