Purpose: To compare the clinical effects of long vs.short intramedullary nails in the treatment of intertrochanteric fractures in old patients more than 65 years old.Methods: A retrospective analysis of 178 cases of intertrochanteric fractures of the femur (AO type A1 and A2) in the elderly was conducted from January 2008 to December 2013.There were 85 males (47.8％) and 93 females (52.2％) with the age of 65-89 (70.2 ± 10.8) years.The patients were treated by closed reduction and long or short intramedullary nail (Gamma 3) fixation.The length of short nail was 180 mm and that for long nail was 320-360 mm.The general data of patients, operation time, intraoperative blood loss, length of hospital stay, preoperative hemoglobin level, blood transfusion rate, postoperative periprosthetic fractures, infections, complications, etc were carefully recorded.Results: There were 76 cases (42.7％) in the long intramedullary nail group and 102 cases (57.3％) in the short nail group.All the cases were followed up for 12-48 (21.3 ± 6.8) months, during which there were 21 deaths (11.8％), mean (13.8 ± 6.9) months after operation.The intraoperative blood loss was (90.7 ± 50.6) ml in short nail group, greatly less than that in long nail group (127.8 ± 85.9) ml (p =0.004).The short nail group also had a significantly shorter operation time (43.5 min ± 12.3 min vs.58.5 min ± 20.3 min, p =0.002) and lower rate of postoperative transfusion (42.3％ vs.56.7％, p =0.041).But the length of hospital stay showed no big differences.After operation, in each group there was 1 case of periprosthetic fracture with a total incidence of 1.1％, 1.3％ in long nail group and 0.9％ in short nail group.At the end of the follow-up, all patients achieved bony union.The average healing time of the long nail group was (6.5 ± 3.1) months, and the short nail group was (6.8 ± 3.7) months, revealing no significant differences (p =0.09).Postoperative complications showed no great differences either.Conclusion: Both the intramedullary long and short nail fixation has a good clinical effect in treating intertrochanteric femur fractures in the elderly.They showed no significant difference in terms of therapeutic effect, hospital stay and postoperative complications.The incidence of periprosthetic fractures treated by either length of nails was low.But short intramedullary nailing can obviously decrease the intraoperative blood loss, operation time and postoperative blood transfusion.