The literature on cerebrospinal fluid opening pressures for pediatric patients is scant. A retrospective study of measured opening pressures during lumbar punctures of pediatric patients in a controlled, uniform setting was conducted. These procedures were performed in an outpatient surgery setting under anesthesia. Patients’ end-tidal carbon dioxide levels were maintained at 40-45 mm Hg. Opening pressures were measured with the patients lying in left lateral decubitus position with their legs extended. Correlations with patients’ ages and body mass index percentiles were investigated. Forty-four patients (median age, 8.9 years; range, 1.1-16.8 years) were included. Patients with chronic headaches, papilledema, or severe abnormalities of cerebrospinal fluid were excluded. The mean opening pressure recorded was 20.3 cm H₂O (median, 21 cm H₂O; range, 6-36 cm H₂O). Poor correlation with both age and body mass index percentiles was evident. The correlation coefficients were 0.09 and 0.14, respectively. Our experience suggests that pediatric reference ranges for opening pressures are closer to those of adults than previously appreciated, and values above 20 cm H₂O should not necessarily be considered abnormal.