The accessory navicular bone is a surnumerary bone of the tarsus whose symptomatic form remains infrequent. Ignorance of this syndrome often results in delayed diagnosis and differs in the establishment of adequate treatment. We report the observation of a 14-year-old athlete with localized pain in the medial face of the left foot. The radiological assessment showed an accessory navicular bone associated with a infiltration of the soft tissues. Clinical improvement was noted after sports rest and after non steroidal anti-inflammatory therapy. Through this work, we recall the clinico-radiological and therapeutic aspect of navicular bone syndrom.