A coracoid process fracture associated with acromioclavicular dislocation has been reported infrequently. A coracoid process fracture associated with coracoclavicular ligament rupture has been reported only in two cases. Two separated injury mechanisms seem to be involved in this instance; one is direct trauma to the shoulder girdle causing dislocation of acromioclavicular joint, and the other is sudden avulsive pull on coracoid process by the conjoined tendons of short head of biceps brachialis and coracobrachialis, and pectoralis minor muscle causing fracture of the coracoid process. We reported one case of coracoid process fracture associated with acromioclavicular dislocation and partial rupture of coracoclavicular ligament. The lesion was treated by open reduction and interanl fixation using two Kirschner - wires for the acromioclavicular joint and a cortical screw for coracoid process, and the result was satisfactory without complication.