The post-polio syndrome (PPS) is an entity characterized for an episode of muscular weakness and/or abnormal muscular fatigue in individuals that had presented acute polio years before. We report the case of PPS in a patient, 40 years, that thirty-five years after had had paralytic poliomyelitis, developed new symptoms of fatigue, muscular atrophy, dyspnea, difficulties in deambulation and muscular and joint pain. The electromyographic findings revealed injuried neurons of the anterior horn of the marrow and reinnervation after muscular tests.