PURPOSE: To evaluate the results of treatment according to the sub-classification of the Mason type II fracture. MATERIALS AND METHODS: From 1999 to 2003, according to the sub-classification of the Mason type II fracture, 33 patients were treated with miniplate in displaced neck fracture (IIa), with compression screw in displaced head fracture (IIb), with miniplate and/or compression screw in displaced head and neck fracture (IIc), with compression screw and miniplate in comminution fracture (III) or excision of head in irreducible state. The clinical results were evaluated by An and Morrey's functional rating index. RESULTS: Functional rate score averaged 92.7 in type IIa, 88.4 in IIb, 86.4 in IIc, 83.5 in type III with reduced fracture, 75.0 in type III with excised head, and 75.5 in type IV. Complications included heterotopic ossification (2 cases), metal loosening (1 case), malunion (1 case), partial ankylosis of elbow (3 cases), posttraumatic arthritis (1 case). CONCLUSION: These results supported the recommendation for internal fixation with compression screw in isolated radial head fracture (IIb) and with miniplate in fracuture combined with displaced neck (IIa, IIc, indicated some III). We concluded that sub-classification is useful for dicision making in radial head or neck fracture's treatment.