Purpose: The purpose of this study was to evaluate the usefullness of polarus nailing in the treatment of proximal humerus fractures including 2 part, 3 part and proximal comminuted fractures. Materials and methods: Fifteen cases of proximal humerus fracture treated with Polarus nailing from March, 2002 to March, 2004 were selected. Man was 3 cases, and woman was 11 cases. There were one case of follow up loss due to decease. Average age was 60 years old (range, 23 to 84), and there were 6 cases of 2 part fracture, 3 cases of proximal segmental fracture, 5 cases of 3 part fracture. We analyzed the outcom results between 2 part fracture and 3 part fracture. The average follow up period after the operation was 1.5(range, 1 to 2) years. Range of motion (ROM), pain and functional outcome were evaluated by visual analogue scale(VAS) and american shoulder and elbow surgery (ASES) activity of daily living (ADL) functional scoring system. Results: All cases showed union on radiologic evaluation, with 2.3 months follow up. In 5 cases of 3 part fracture, average union time was 1.9 months regardless of proximal screw loosening in 4 cases. In 2 part fracture union time was 2.2 months (P>0.05). VAS pain score was 1.3, ROM was $160^{circ}$ in forward flexion, $40^{circ}$ in external rotation, L3 level in internal rotation, and ASES, ADL functional score was 21 in 2 part fracture. VAS pain score was 1.25, ROM was $160^{circ}$, $43^{circ}$ and L1 level, and ASES, ADL functional score was 21 in 3 part fracture. There were no statistically significant difference between two groups (P>0.05) VAS pain score was 1.6, ROM was $170^{circ}$, $47^{circ}$ and L3 level, and ASES, ADL functional score was 23 in proximal comminuted fracture. Conclusion: Polarus nailing could be used as an effective modality in certain cases of proximal humeral fracture including 2 part, proximal segmental and in cases of 3 part fractures with large greater tuberosity fragment.