A reduced retroversion angle of humeral head may predispose to recurrent anterior shoulder dislocation and may also be a factor in persistent instability after soft tissue procedures. Rotation osteotomy of proximal humerus is one of many surgical modalities proposed for recurrent anterior shoulder dislocation. To support such an operation, fundamental knowledge of shoulder anatomy is essential. The semi-axial view by Soderlund have been regarded as simple and reliable method for measuring humeral head retroversion angle. The purpose of this study was to evaluate validity of the semi-axial view and to assess reference values for humeral head retroversion angle in Korean. Humeral head retroversion angle was determined from 80 healthy subjects, 48 men and 32 women. Radiographs which shown less than 10degrees between humeral shaft axis and epicondylar axis were defined as acceptable radiographs by Soderlund. Acceptable radiographs were selected and two orthopedic surgeons measured retroversion angle, separately. Acceptable radiographs were obtained in only 70 shoulders (43.8%). The mean angle was 35.2±8.24degrees for dominant hand and 32±6.27degrees for nondominant in Korean. The mean angle was 35.3± 7.78degrees for right side and 31.9±6.8degrees for left. The interobserver difference was 2.9degrees. The semi-axial view by Soderlund was not reproducible solely. But if correct arm position is considered, the method presented is easy to use daily.