Twenty-two patients with medulloblastomas were evaluated by computed tomography. Pretreatment evaluation in 13 patients has shown the various presentations of the tumor. Eighteen of the patients have had post-therapy computed tomographic studies. Computed tomography is sensitive in detecting residual and locally recurrent tumor as well as tumor seeding by cereborspinal fluid pathways. Computed tomography has proved to be valuable in patient management and in evaluating the effectiveness of various forms of treatment. The present group of medulloblastomas is compared to other pediatric posterior fossa tumors and differential diagnoses are discussed.