Arthroerisis of the subtalar joint can be a valuable tool for the foot and ankle surgeon in treating flexible pes planus deformity in adults, as well as in children. Whether by itself, or in conjunction with other procedures, such as Achilles tendon lengthening (to allow dorsiflexion to at least neutral), midfoot or hindfoot osteotomies (to correct significant bony deformities), and posterior tibial tendon advancements (with associated symptomatic accessory navicular), arthroerisis can be helpful to correct deformity. When compared with procedures that involve osteotomy or arthrodesis, there is less morbidity to the patient who undergoes arthoerisis during surgery as well as postoperatively. There is no risk of nonunion, less immobilization is usually required, and arthroerisis is technically easy to perform. As with all surgical procedures, proper patient selection is extremely important.