Background Physiologic (flexible) pes planus (flatfoot) is a descriptive term for feet that have a visually lowered medial longitudinal arch often in association with rearfoot eversion [1]. Reported to affect approximately 15% of the adult population [2] physiologic pes planus can be categorised as either symptomatic (painful, non-functional) or nonsymptomatic (non-painful, functional) with the literature purporting that flexible non-symptomatic pes planus is a predominantly benign condition with no justification for intervention [3]. When pes planus is symptomatic however, functional foot orthoses are often prescribed and are the most commonly quoted intervention within the literature[4]. Despite some controversy for their use in pes planus, functional foot orthoses remain the cornerstone of podiatric management of this common disorder. The aim of this review is to evaluate the evidence for the use of foot orthoses in adults with symptomatic pes planus.