Reports on citrullinemia usually describe the imaging findings in the adult form of the disease. However, neuroimaging findings of neonatal cases are seldom reported. We report on the diffusion-weighted magnetic resonance imaging (MRI) findings of a one-year old infant with neonatal citrullinemia during an acute episode and discuss possible underlying mechanisms for abnormal diffusion findings. (C) 2008 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.