Studies in the United States have revealed that gastroesophageal reflux disease (GERD) patients often suffer from nocturnal symptoms, sleep disturbance, and impaired quality of life. In a large subset of patients, these symptoms persist in spite of acid suppressive therapy. The aim of the present study was to assess the prevalence of heartburn and associated sleep complaints and the response to standard medical therapy with pantoprazole in primary and secondary care esophagitis patients in Belgium. Questionnaires were provided to consecutive patients presenting to primary and secondary care physicians with esophagitis. The questionnaire evaluated the presence of typical reflux symptoms, alarm symptoms, risk factors, and sleep quality impairment as a result of reflux episodes. Results are shown as mean ± standard deviation and compared by Student's t-test or chi-square test. A total of 4061 primary and 5261 secondary care patients (50% female, mean age 53 ± 0.2 years, body mass index of 25.7 ± 0.1 kg/m2) were recruited. Eighty-four percent of patients reported sleep disturbance attributable to nighttime reflux, including typical nighttime supine reflux symptoms (72%), difficulties to fall asleep (39%), waking up during the night (45%), morning fatigue (35%), and reflux symptoms when waking up in the morning (47%). Mild, moderate, or severe nighttime heartburn were reported by, respectively, 30, 35, and 12%, and these numbers were 26, 28, and 6% for nighttime regurgitation. Alcohol (19%), smoking (22%), higher esophagitis grades (grades 2, 3, and 4 in, respectively, 31, 7, and, 7%), alarm symptoms (27%), and more severe heartburn and regurgitation during daytime were all significantly associated with all dimensions of sleep disturbance (P < 0.0001). Obesity was only related to symptoms in supine position and when waking up (P < 0.0001). After 1.4 ± 0.0 months of treatment with pantoprazole, any sleep disturbance had improved in more than 75% of patients, with resolution of nighttime heartburn and regurgitation in, respectively, 75 and 83%. The majority of patients presenting with reflux symptoms and esophagitis in primary or secondary care experience nighttime heartburn and regurgitation, and sleep disturbance by nighttime symptoms is present in 84%. Smoking, alcohol use, higher grades of esophagitis, more severe typical reflux symptoms during daytime, and the presence of alarm symptoms are risk factors for GERD-related sleep disturbance. On standard therapy with pantoprazole, nighttime symptoms improved in more than 75%. These observations support a direct relationship between GERD and sleep disturbance.