We report a 13 year-old female child with a idiopathic acute sensory neuronopathy mimicking a sensory form of Guillain-Barré syndrome, identified with electrodiagnosis and spine MRI. Motor conduction results were normal, but sensory nerve action potentials were not evoked in all four extremities. On MRI of the whole spine, the diffuse gadolinium-enhancement of dorsal roots in the spinal canal was detected without evidence of intramedullary lesion. The clinical symptoms and electrodiagnostic abnormalities had persisted for more than 18 months follow-up.