Plantar fasciitis is an overuse injury causing inflammation at the origin of the plantar fascia and is characterized by plantar heel pain that is provoked by taking the first few steps in the morning and by prolonged standing. It is the most common clinical problem that causes inferomedial heel pain in adults. It is estimated that more than two million people receive treatment for plantar fasciitis in the United States each year. Despite its familiarity to physicians, the exact etiology of plantar fasciitis remains obscure. The variety of treatments noted in the literature attests to the uncertainty of the etiology and pathogenesis of plantar fasciitis. It has been suggested that the success of conservative care for the treatment of patients with plantar fasciitis requires a combination of treatment modalities. Although many authors have stated that mechanical therapy should be considered a cornerstone of any effective treatment plan, some debate remains regarding the most effective form of mechanical treatment. The literature provides evidence to support the use of dorsiflexion night splints and medial arch supports in the treatment of plantar fasciitis. A night splint is used to address early morning pain by preventing contracture of the plantar fascia and Achilles tendon overnight. An arch support, on the other hand, addresses the end of the day pain by preventing overstretch of the plantar fascia during prolonged weight bearing. Therefore, both night splints and arch supports may be necessary to treat plantar fasciitis as they complement each other by both controlling nocturnal contracture of the plantar fascia and Achilles tendon and reducing stresses imposed on the plantar fascia during the day, respectively. This prospective randomized study, to the best of our awareness, is the first that addresses this problem by examining the combined effect of these treatment modalities and comparing it to the effect of a night splint or arch support each by itself. We hypothesize that the night splint and arch support together will be more effective in the treatment of plantar fasciitis than night splint or arch support alone in terms of increasing the range of pain-free passive ankle dorsiflexion, relieving heel tenderness and pain, and reducing disability imposed by the heel pain/plantar fasciitis. A secondary hypothesis of this study is that those with limited passive dorsiflexion of the ankle will benefit from a night splint more than those with normal passive dorsiflexion of the ankle and those with a low medial longitudinal arch will benefit from an arch support more than those with a normal medial longitudinal arch in terms of the previously mentioned outcomes. The range of motion will be measured with a goniometer; heel tenderness will be measured with a pressure algometer; and pain and disability will be measured by the Foot Function Index.