Epiphyseal fracture-retrosternal dislocation of the medeial end of the clavicle is an unusual injury. It may occur as a result of a blow either indirectly on the posterolateral aspect of the shoulder girdle or directly over the sternal end of the clavicle. It is clinically impossible to differentiate from the true posterior dislocation even with the computed tomography, but the treatment for either lesion is the same. Recently we uneventually treated a 15-year-old boy with conservative treatment and got a satisfactory result. The purpose of this paper is to draw the attention of the readers to the rarity and serious nature of such injury and the potential difficulties in establishing diagnosis and achieving reduction.