Improvements in survival for patients who had childhood brain tumors has led to an increasing emphasis on the quality of life for these long-term survivors. Initial survival studies relied on global descriptions of functional abilities to assess cognitive deficits and reported that from 20% to 40% of long-term survivors had obvious partial disability and less than 10% were severely disabled. Formal neuropsychological testing has revealed that from 40% to 100% of long-term survivors have some form of cognitive deficit in various intelligence quotients, visual/perceptual skills, learning abilities, and adaptive behavior. Prospective, controlled studies have found a younger age at diagnosis, radiotherapy, methotrexate chemotherapy, tumor location and time interval to testing to be important (alone or in combination) and related to a high risk of subsequent cognitive deficits. Some variables play an as yet unresolved role. However, despite the progress of the last decade, future prospective studies are needed to define the role of certain variables in the development of cognitive deficits that maximize survival while minimizing cognitive deficits.