Prolonged intraesophageal pH recording, an important test in the evaluation of children with suspected gastroesophageal reflux (GER) disease, may be performed and evaluated by markedly different methodologies. Twenty-four-hour intraesophageal pH recordings from 67 consecutive infants were evaluated by three scoring methods: early postprandial, late postprandial, and total recording. In addition, the scoring methods were evaluated for their ability to identify 20 infants with clinically defined GER-induced acute life-threatening events (ALTEs). There were significant positive correlations between each pair of scoring systems (early postprandial with late postprandial, early postprandial with total recording, and late postprandial with total recording). However, our data indicate that the three methods identify different groups of patients. The early and late postprandial methods disagreed in designating "normal" versus "abnormal" in approximately 20% of patients. The total recording method was more likely to label patients as normal than either of the other methods; it yielded normal results in approximately one half of patients abnormal by either the early or the late postprandial methods. Patients with GER-induced ALTEs were identified by the early postprandial method in 90% of cases, the late postprandial method in 95% of cases, and the total recording method in only 45% of cases. By applying three different scoring methods to the same 24-h intraesophageal pH recording, we demonstrated less-than-perfect correlation among the methods. Long-term follow-up is needed to determine if these differences are of clinical significance. We feel that effort should be directed toward standardizing the approach to intraesophageal pH monitoring in infants.