Avulsion fractures involving insertions of the radial extensors at the base of the index and middle metacarpals are quite rare. However, avulsion fractures at the insertion site of the extensor carpi radialis longus on the index metacarpal and avulsion fractures involving the extensor carpi radialis brevis insertion at the base of the middle finger metacarpal have been reported. Although there are many reports of fractures of the base of the first metacarpal, there are few recommendations available for treatment of these injury. We report two avulsion fractures at the extensor carpi radialis longus insertion, which were treated with an open reduction and internal fixation of the avulsed bony fragment using a miniplate and screw.