We conducted a retrospective study on 24-hour esophageal pH monitoring performed to patients with non allergic asthma, chronic cough and chronic pharyngitis or laryngitis. We studied 168 patients. On 24-hour esophageal pH monitoring, gastroesophageal reflux was detected in 67 cases (40%), more frequently in patients with chronic cough and asthma than in patients with chronic pharyngitis or laryngitis. A statistically significant increase in all the pHmetric parameters, except for the number of reflux episodes, was found in asthmatic patients compared to patients with chronic pharyngitis or laryngitis. Comparison of the pHmetric parameters in patients with gastroesophageal reflux disease revealed that the number of reflux episodes of morethan five minutes and the duration of longest reflux episodes were higher in asthmatic patients than in patients with chronic cough. Gastroesophageal reflux disease is more frequent in asthma and chronic cough than in chronic pharyngitis or laryngitis. Reflux episodes in chronic cough are shorter than these in asthma. This difference should explain the different severity between the two situations.