We described a patient with encephalopathy associated with visceral larva migrans (VLM) caused by Ascaris suum. He suffered from drowsiness, quadriparesis, eosinophilia and elevated serum IgE levels. Brain magnetic resonance (MR) imaging revealed multiple cerebral cortical and white matter lesions. Serological tests indicated recent infection with A. suum. Pulse steroid therapy relieved the patient's central nervous system symptoms and marked improvement of lesions on brain MR images. We concluded that the encephalopathy in this patient was probably caused by VLM due to Ascaris suum.