Acute autonomic sensory and motor neuropathy (AASMN) is characterized by prominent dysautonomia with somatic sensory and motor impartment. Prominent dysautonomia is observed during the early phase of AASMN. We herein describe a case of AASMN that involved prolonged autonomic failure and disturbance of sensation despite a rapid recovery from motor weakness. The early and delayed heart-to-mediastinum ratios on (123)I-meta-iodobenzylguanidine myocardial scintigraphy were decreased and improved within seven months. However, orthostatic hypotension was prolonged. These results suggest a differential improvement in the cardiac and vasomotor sympathetic functions.