Peroneal spastic flatfoot is an uncommon condition. It often presents as a rigid and usually painful valgus deformity in the hindfoot with peroneal muscles spasms. Although tarsal coalition is an important cause, a few patients have not undergone bone coalitions. We describe a 27-year-old female who experienced recurrent peroneal spastic flatfoot after an injury. She was treated successfully with a combination of botulinum toxin type A and immobilization of the foot in a neutral position with a cast. After 3 years, the condition had not recurred, and she was pain free and walked normally, with no increase in muscle tone. This unique treatment could be of potential use to treat many patients with such conditions. (C) 2015 by the American College of Foot and Ankle Surgeons. All rights reserved.