Background: fMRI can be used to non-invasively visualise human brain activity. Considering the importance of estimating the extent of functional disturbances in children with focal brain lesions, the purpose of this study was to investigate the visual processing in sedated children (a) during normal brain development and (b) in selected children with focal brain lesions. Subjects and Intervention: 9 children with normal visual function (15mo-6y) and 3 children with visual disturbances (1 suspected hemianopia, 1 suspected cortical blindness, 1 ophthalmoplegia with ptosis) were examined during pentobarbital sedation. A Blood Oxygenation Level Dependent (BOLD)-contrast sensitive MRI sequence was used. Visual stimulation was done by red LED flashing goggles (8Hz). Results: In 8 of the 9 children without visual problems a stimulus related inverse BOLD-signal was detected in the visual cortex. The child with ophthalmoplegia also showed activity, whereas no activity was seen in the child with cortical blindness. Conclusion: fMRI permits investigations of visual processing in sedated children. Results from a parallel study in adults indicate that the inverse BOLD-effect is related to pentobarbital sedation, rather than to brain maturation.