The prevalence of gastroesophageal reflux (GER) in 86 children with respiratory disease (recurrent pneumonia, chronic cough, bronchial asthma) has been evaluated by mean of prolonged (22-24 hours) esophageal pH-monitoring. The following parameters were evaluated: the total percentage of time pH < 4 and the percent time the esophageal pH was < 4 while sleeping. None of the children had gastrointestinal symptoms suggesting GER and no neurological disorder was noted in any of the studied patients. The mean age was 68.98 +/- 46.46 months (range 14-189); 53 (61.6%) males and 33 (38.4%) females were considered in the study. Atopy was evidenced in 42/86 (48.8%) children (total IgE > 2SD in 42/86 and prick tests positiveness in 32/86. A pH-metry indicating pathological GER was present in 52/86 (60.5%) children: 39/62 (62.9%) patients with bronchial asthma, 5/10 (50%) subjects with chronic cough and 8/14 (57.2%) children with recurrent pneumonia. No significant difference in the diagnosis of GER was recorded between atopic or non-atopic patients. The children with abnormal pH-metric recording were also evaluated by upper gastrointestinal series and/or endoscopy. A conventional barium radiology was performed in 44/52 patients and confirmed GER in 19/44 (43.2%). Esophagitis was evidenced in 21/46 (45.7%) studied patients. The presence of esophagitis was significantly (p = 0.032) related to the total percentage of time pH < 4, but the most significant (p = 0.002) association was with the percent time the esophageal pH was < 4 during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)