Objective To investigate the operative method and to evaluate the cl inical outcome of proximal femoral nail antirotation (PFNA) in treating reverse obl ique fractures of intertrochanteric region of the femur. Methods From January 2007 to February 2008, 30 cases of reverse obl ique fractures of intertrochanteric region of the femur were treated by closed reduction and fixation with PFNA, including 14 males and 16 females and aging 40-88 years old with an average of 68.6years old. All patients had closed fractures. According to AO classification, there were 6 cases of 31-A3.1 type, 7 cases of 31-A3.2 type and 17 cases of 31-A3.3 types. The time from injury to operation was 2-14 days (with an average of 5.3 days). All 31-A3.1 and 31-A3.2 type farctures and 9 cases of AO 31-A3.3 type fractures were fixed with the standard PFNA, and 8 cases of 31-A3.3 type fractures with the PFNA-long. The cl inical and radiological examinations were done at 1, 2, 3, 6, 12, and 18 months after operation. The cl inical outcomes were evaluated according to the Sanders scoring. Results Iatrogenic fracture of femoral shaft occurred in 1 case; no additional procedures were appl ied as fracture kept favorable stabil ity. Superficial infection occurred in 1 case at 5 days after operation, wound healed after dressing change and intravenous antibiotic therapy. Other wounds healed by first intention. All cases were followed up for 12-19 months (mean 14.1 months). All fractures healed uneventfully after 12-30 weeks (mean 16.2 weeks). Five patients complained of hip pain, 2 patients had lateral leg pain, and the pain was el iminated after symptomatic treatment. One case compl icated by ipsilateral fracture of the tibial plateau had functional disturbance of knee, and one case compl icated by ipsilateral fracture of the acetabulum and pelvis had functional disturbance of hip, and the function was improved after functional exercise. No compl ications such as cut-out or breakage of the implants occurred. According to Sanders criteria, the cl inical results were excellent in 22 cases, good in 6 cases, and poor in 2 cases. The excellent and good rate was 93.3%. Conclusion PFNA is an effective treatment method for reverse obl ique fractures of intertrochanteric region of the femur, with a high rate of bone union, minor soft tissue damage, early functional exercise and acceptable compl icationrelated to implant.