3 cases with benign choroid plexus papillomas (CPP) in the fourth ventricle are described. All patients were less than 2 months of age. They were among 14 cases with intracranial CPP in a series of 100 tumors of the posterior fossa. Correct diagnosis was not obtained by means of pneumoencephalography, with apparently normal repletion of the fourth ventricle being visualized. 2 of the 3 patients died after application of the ventriculoperitoneal shunt and before extirpation of the tumor. All 3 patients soon presented hydrocephalus in 1 case already 'intra utero'.