For 10 yr, numerous studies have been conducted to try to explain the further deterioration of the sequelae from a previous, acute poliomyelitis. The different etiologic hypotheses, which have been put forward, have not been confirmed yet. A retrospective study has been completed by mailed questionnaires sent to 360 patients previously affected by acute polio; 248 polio survivors replied. Deterioration, as functional loss especially during walking and exertion, was reported by 77% of our respondents. Among the newly affected cases, 60% have given up or slowed down their socio-professional activities because of these new problems with their health. These functional losses, reported by patients, have been statistically related to several factors: the aging process, weight gain, female predominance and the involvement of abdominal muscles at a previously acute polio stage. The recently affected population has the same degree of disability (measured through the "Functional Independence Measure" (translated in French and self-administered)) as the nonaffected one. This fact suggests that the problems that are being experienced may be partly subjective.