To assess the use of combined multichannel impedance and pH studies (MII-pH) in a large group of symptomatic young infants, to characterize the occurrence of gastroesophageal reflux disease (GERD), and to establish temporal association of the reflux behaviors with GER using symptom indices. This is a retrospective cohort study on 181 infants who underwent MII-pH studies for clinical behaviors that were suggestive of GERD. Symptom Index (SI) and symptom association probability (SAP) were used to establish symptom association with reflux. >100 GER episodes in 24 hours or reflux index >10% was considered pathological reflux. A total of 181 infants (median age 60 days, IQR 34 -108) underwent MII-pH studies with median study duration of 22.41 hours (IQR 21.5 -23.32). 4070 hours of data were analyzed, with 8480 reflux events [2996 (35%) acidic, 5484 (65%) nonacidic]. 2541 symptoms were noted, 894 (35%) were temporally related to reflux events. A total of 113 infants (62.4%) had positive symptom association with SI >50 and/or SAP >95 for at least one symptom. There was modest symptom association for choking and gagging but apnea, bradycardia and desaturations had poor symptom association. Only 29 infants (16%) had pathological reflux and only 18 infants (10%) had both pathological reflux and positive symptom association. MII-pH can be used to characterize GERD in young infants, along with establishing temporal association with symptoms. Pathological reflux in symptomatic young infants is not common, but symptom association may occur without frequent or acidic reflux.