Background: Neuropsychological deficits after treatment of paediatric brain tumour are well known, but not the role of hydrocephalus in these deficits. Aims: To study long-term neurological, cognitive, and behavioural deficits in children with a low grade tectal tumour and acquired obstructive hydrocephalus. Methods: In a consecutive series of 12 children with low-grade tectal tumour diagnosed in our hospital between 1994 and 2008, neurologic, neuropsychological, and radiologic data were prospectively collected. Intelligence, memory, attention, language, visual-spatial, and executive functions were assessed. Median follow-up was 2 years and 9 months. Results: At follow-up, most frequent neurologic disability was fatigue in children with a low-grade tectal tumour. They scored lower on sustained attention, long-term memory and had more behavioural problems. Factor influencing cognition was persisting severe hydrocephalus at time of assessment. The cognitive problems resulted in 60% of children needing assistances of special services at school. Conclusions: At long-term, children with a low-grade tectal tumour display invalidating neuropsychological impairments resulting in educational problems. Adequate treatment of hydrocephalus may result in better cognitive functioning. Our findings suggest that part of the symptoms of the cerebellar cognitive affective syndrome may not have resulted from a cerebellar lesion itself but rather from a cerebral dysfunction or compression of supratentorial structures in the cerebello-cortical circuitry due to the obstructive hydrocephalus. (C) 2014 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.