Many persons infected by polio in childhood or youth can develop new or increased impairments several decades later.  There is very little knowledge about how an AFO impacts balance and walking ability in persons with late effects of polio (LEoP). Therefore, the aims of this study were (1) to assess if a flexible AFO improves dynamic balance as well as indoor and outdoor walking ability in persons with mild to moderate LEoP and (2) to describe the participants’ own perceptions of walking ability and safety as well as advantages and disadvantages with an AFO.