['The prevalence of gastroesophageal reflux (GER) in children with asthma is higher than in healthy controls, but the nature and direction of this association is unclear.', 'The aim of our study was to assess the relationship between esophageal acid exposure and the clinical features of asthma in children.', 'In total, 66 children (mean age 122.8 months [SD 44.89 months]) with chronic pulmonary symptoms, fulfilling diagnostic criteria of persistent asthma, underwent 24-hour esophageal pH monitoring and answered a detailed questionnaire-based survey. The questionnaire topics included environmental factors, familial history, current and previous clinical symptoms, atopy, asthma severity, and medication.', 'Abnormal results of 24-hour esophageal pH monitoring were found in 28 out of 66 children (42.4%). Age, sex, severity of asthma, environmental factors, spirometry results, and the type of medication did not correlate with esophageal acid exposure. However, children with abnormal pH results developed asthma significantly earlier (asthma onset 3.63 years [SD 2.52 years] vs 5.77 years [SD 3.82 years]; p < .01). Nonatopic individuals had more intensive esophageal acid exposure than atopic ones (Boix-Ochoa score 28.19 [SD 18.26] vs 18.26 [SD 12.84]; p < .048). The intensity of GER was also significantly correlated with frequent or difficult-to-control nighttime asthma attacks.'] Do clinical features of asthma in children differ with regard to the intensity of distal gastroesophageal acid reflux?