Laparoscopic fundoplication controls heartburn and regurgitation, but the effects on the respiratory symptoms of gastroesophageal reflux disease (GERD) are unclear. Confusion stems from difficulty preoperatively in determining whether cough or wheezing is actually caused by reflux when reflux is found on pH monitoring. To date, there is no proven way to pinpoint a cause-and-effect relationship. The goals of this study were to assess the following: (1) the value of pH monitoring in establishing a correlation between respiratory symptoms and reflux; (2) the predictive value of pH monitoring on the results of surgical treatment; and (3) the outcome of laparoscopic fundoplication on GERD-induced respiratory symptoms. Between October 1992 and October 1998, a total of 340 patients underwent laparoscopic fundoplication for GERD. From the clinical findings alone, respiratory symptoms were thought possibly to be caused by GERD in 39 patients (11%). These 39 patients had been symptomatic for an average of 134 months. They were all taking H2-blocking agents (21%) or proton pump inhibitors (79%). Seven patients (18%) were also being treated with bronchodilators, alone (3 patients) or in combination with prednisone (4 patients). Median length of postoperative follow-up was 28 months. In 23 patients (59%) a temporal correlation was found during 24-hour pH monitoring between respiratory symptoms and episodes of reflux. Postoperatively heartburn resolved in 91% of patients, regurgitation in 90% of patients, wheezing in 64% of patients, and cough in 74% of patients. Cough resolved in 19 (83%) of 23 patients in whom a correlation between cough and reflux was found during pH monitoring, but in only 8 (57%) of 14 of patients when this correlation was absent. Cough persisted postoperatively in the two patients who did not cough during the study. These data show that pH monitoring helped to establish a correlation between respiratory symptoms and reflux, and it helped to identify the patients most likely to benefit from antireflux surgery. Following laparoscopic surgery, respiratory symptoms resolved in 83% of patients when a temporal correlation between cough and reflux was found on pH monitoring; heartburn and regurgitation resolved in 90%.