Cognitive deficits are frequently reported in children treated for posterior fossa (PF) tumors. A range of tumor, treatment, medical and treatment complications have been implicated in causing a variety of cognitive deficits. The aim of this study is to identify factors that influence intelligence, attention and information processing in these children. Thirty-five children (aged 4-16) with PF tumors attending the Royal Children's Hospital Melbourne, Australia, were enrolled into a prospective, repeated measures design. Neuropsychological assessments were conducted at diagnosis and at 12 month intervals for three years. The results find that the PF tumor, hydrocephalus, white matter injury and radiation therapy have various impacts on intelligence, attention and information processing skills, and contribute to the long term outcome in children treated for PF tumor. The neurological structures that subserve the efficient function of attention and information processing are particularly vulnerable to those factors.