The majority of gastroesophageal reflux (GER) episodes in infants and children are nonacidic (pH >4). However, extraesophageal symptoms (e.g., breathing irregularities, apnea, aspiration) apparently can be caused by both acidic (pH <4) and nonacidic reflux. The standard diagnostic tool for suspected GER is pH monitoring. However, physicians should be aware of the limitations of pH monitoring in the pediatric population, because most reflux episodes in this age group are undetectable by this method. In contrast, the pH-independent multiple intraluminal electrical impedance technique (IMP) allows all bolus movements in the esophagus to be detected. Data can be analyzed for bolus composition and reflux height, duration, and clearance. Combining IMP with pH monitoring on a single catheter has proved to be a valuable tool for diagnosing GER and associated symptoms in infants and children.