Recently, multichannel intraluminal impedance (MII) monitoring was added to the repertoire of tests to evaluate the (patho)physiology of gastroesophageal reflux (GER) in children. Its advantage above the sole monitoring of the esophageal pH lies in the ability of the detection of both acid and nonacid GER and to discern between liquid and gas GER. Currently, combined 24ï¿½h pH-MII monitoring is recommended for evaluation of gastro-esophageal reflux disease (GERD) and its relation to symptoms in infants and children, despite the lack of reference values in these age groups. There is new evidence in the current issue of this Journal supporting the role of pH-MII monitoring for the evaluation of children presenting with gastrointestinal symptoms suggestive of GERD and the prediction of the presence of reflux esophagitis. However, several issues should be taken into account when performing pH-MII clinically.