Objectives: The association between gastroesophageal reflux disease and idiopathic pulmonary fibrosis has not been fully characterized. The aims of this study were to determine in patients with idiopathic pulmonary fibrosis (1) the prevalence of reflux symptoms, (2) the esophageal manometric profile, and (3) the prevalence of proximal and distal esophageal reflux. Methods: Between May 1999 and March 2006, 30 patients with idiopathic pulmonary fibrosis were referred to the Swallowing Center at the University of California San Francisco. Each patient underwent a structured symptom assessment, esophageal manometry, and 24-hour dual sensor ambulatory pH monitoring. Results: Twenty (67%) patients had abnormal esophageal reflux. Typical reflux symptoms, although more common in those with reflux, were not reliable as a screening test (sensitivity 65%, specificity 71%). Sixty-five percent of patients with abnormal reflux had a hypotensive lower esophageal sphincter. Abnormal esophageal peristalsis was more common among those with reflux (50% vs 10%; P = .03). In 9 (30%) patients, acid refluxed into the proximal esophagus for over 1% of the study time. Conclusions: A majority of patients with idiopathic pulmonary fibrosis have pathologic reflux. Symptoms do not distinguish between those with and without reflux. In these patients, reflux is associated with a hypotensive lower esophageal sphincter and abnormal esophageal peristalsis, and often extends into the proximal esophagus. © 2007 The American Association for Thoracic Surgery.