Objective To study the pathophysiologic significance of gastroesophageal and duodeno-gastric-esophageal refluxes in pediatric patients.Methods Gastroesophageal double pH monitoring was performed on 68 children with gastro-esophageal reflux (GER) diseases and 39 normal children. The pH shifts in the intra-gastric and esophageal lumina were recorded for a total of 24 hour period (P1) and for the period of gastric empty (P2) in supine and upright body postures. Results The following reflux types were identified: acid GER in 40 cases (58.8%), alkaline GER (AGER) in 8 cases (11.8%), mixed GER (MGER) in 14 cases (20.6%) and silent GER (SGER, i.e., reflux with normal pH values in P1) in 6 cases (8.8%) as well as duodenogastric reflux (DGR). The results showed a number of transient GER and DGR (19 of 39 children) in the control group, recorded mainly in the upright position at meal times and 2 hours postprandially. All pH variables for acid reflux were higher in the acid GER and MGER groups than those in the control group (P<0.01). The alkaline episode was significantly noted in cases with AGER and MGER in the supine position during P2. There was no significant difference in terms of incidence of esophagitis between GER groups. The gastroesophageal double pH monitoring produces the higher positive diagnostic rate of 91.2% than single esophageal pH testing (79.4%). Conclusions Transitory GER and DGR at meal times and 2 hours later might be a physiologic phenomenon. Acid and alkaline reflux occurring in the supine position during P2 should be considered of pathologic significance. This combined gastroesophageal pH monitoring is used not only to improve the diagnostic rate but also to guide clinicians to choose efficient anti-reflux therapy based on the type of reflux as well as to provide refined information for the further study of the pathophysiology of duodenogastro-esophageal reflux.