Objective To evaluate the clinical results of free vascularized fibular grafting (FVFG) for the treatment of osteonecrosis of the femoral head (ONFH).Methods From July,2009 to January,2013,85 cases (120 hips) of ONFH were treated with free vascularized fibular grafting.These cases included 61 males (87 hips) and 24 females (33 hips) with an average age of 36.5 years (22-51 years);7 hips (Ⅰ A 2 hips,Ⅰ B 3 hips,Ⅰ C 2 hips) were at stage Ⅰ,98 hips (Ⅱ A 24 hips,ⅡB 39 hips,ⅡC 35 hips) at stage Ⅱ and 15 hips (ⅢA 9 hips,ⅢB 4 hips,Ⅱ C 2 hips) at stage]Ⅲ according to the classification system of Association Research Circulation Osseous (ARCO).The mean preoperative Harris hip score was (60.21±6.85) points (42-71 points),The follow-up items included the X-ray examination,the Harris scores of the hip,and the evaluation of the complications.Results Eighty-three cases (117 hips) were followed up.The average duration of follow-up was 25 months (range from 12 months to 42 months).The mean postoperative Harris hip score was increased to (81.26±5.84) points (67-91 points) by the end of the follow-up,compared with the preoperation,the score improved significantly,the difference was statistically significant (P＜0.05).Comparing with postoperative X-ray,101 hips (86.3％) were improved,12 hips (10.3％) had no significant changes and deterioration occurred in 4 hips (3.4％).Conclusion The free vascularized fibular grafting is an effective method for treating osteonecrosis of and preventing the collapse of the femoral head.