PURPOSE: We try to retrospectively evaluated the amount of dorsal angulation angle of the first metatarsal commonly occurring as the complication of proximal dome osteotomy for hallux valgus. MATERIALS AND METHODS: Between January 2004 and March 2004, 34 patients who underwent proximal dome osteotomy for moderate to severe hallux valgus. Two of 34 patients were male, and thirty-two were female. The average age was 57.6 years. We measured and compared hallux valgus angle, 1st-2nd intermetatarsal angle, dorsal angulation angle of 1st metatarsal on preoperative, postoperative, postoperative 3 weeks', postoperative 3 months' X-ray. RESULTS: Osteotomy sites were completely united on plane X-ray in all cases. The hallux valgus angle averaged 41.2 degrees (30~60 degrees) at preoperative, 4.3 degrees (-10~20 degrees) at postoperative, 5.5 degrees (-1~20 degrees) at 3 weeks after operation, 7.8 degrees (-2~20 degrees) at 3 months after operation. The 1st-2nd intermetatarsal angle averaged 17.1 degrees (12~24 degrees) at preoperative, 6.3 degrees (0~13 degrees) at postoperative, 7.2 degrees (0~15 degrees) at 3 weeks after operation, 8.7 degrees (0~18 degrees) at 3 months after operation. The dorsal angulation angle averaged 0.4 degrees (0~3 degrees) at postoperative, 1.6 degrees (0~7 degrees) at 3 weeks after operation, 2.1 degrees (0~8 degrees) at 3 months after operation. There were no statistically correlation between increase of dorsal angulation angle of the distal segment of the first metatarsal and increase of hallux valgus angle or 1st-2nd intermetatarsal angle. CONCLUSION: Our results shows that the dorsal angulation of distal fragment occurring after the proximal dome osteotomy in the treatment of hallux valgus may be minimized with meticulous surgery and patient's education.