In order to determine the frequency and natural history of benign extracerebral fluid collections, computed tomography reports from a period of 26 months at Oklahoma Children's Memorial Hospital were reviewed (total scans: 3,411). Bilateral frontal extracerebral fluid collections were found in 94 infants under 1 year of age. Eighty-two infants had computed tomography scans as part of the evaluation for macrocrania. Thirteen patients had the typical findings of benign extracerebral fluid collections but otherwise were completely asymptomatic. Longitudinal observation for up to 30 months failed to reveal any changes in neurologic status of these patients. Benign extracerebral fluid collections are a relatively common cause of macrocrania in infants. The presence of these fluid collections is not of immediate concern, providing that clinical evaluations fail to identify either neurologic or developmental abnormalities.