OBJECTIVE New generation cephalomedullary nails are, currently, widely used for the treatment of trochanteric proximal femoral fractures. This study aims to compare the midterm outcomes and complication rates in patients with unstable 31A2 fractures treated with two different lengths of nails. METHODS Retrospective study including 123 pertrochanteric proximal femoral fractures 31A2 treated with Gamma3 nail® between January/2017 and January/2019. 19 patients were excluded, resulting in a total of 104 patients with a minimum follow-up of 1 year. Two groups, Long Dynamic Gamma3 Nail (LGN) and Short Static Gamma3 Nail (SGN), with 52 patients each were compared. Mean age was 81 years (range 50-99), being 78% female. Preoperative variables included: age, medical comorbidities, mobility, anesthetic risk, associated fractures, hemoglobin and hematocrit values. Postoperatively, functional and radiological results, quality of life, hemoglobin and hematocrit concentration, transfusion requirements, mobility, and pain were evaluated. Additionally, perioperative complications were also analyzed, such as malunion, non-union, infection rates, cut-outs, and peri-implant fractures. RESULTS A correct radiological fracture reduction was obtained in 73% of the cases (73% SGN/74% LGN). Two patients in LGN group had intraoperative complications (greater trochanter fractures). 38% of the patients with LGN presented nail tip impaction upon the distal anterior femoral cortex, associated with anterior knee pain. Blood loss and operative time was statistically different between groups. Despite the previous, no differences in clinical outcomes and quality of life were found. CONCLUSIONS The present study comparing two lengths of the Gamma3 Nail in 31A2 fractures showed no overall differences in clinical and radiological outcomes, and complication rates. However, the use of LGN was associated with a statistically significant higher blood loss and operative time, and a tendency for increased need for transfusion, and anterior knee pain and reoperation rate. Therefore, we recommend the use of locked SGN in the treatment of 31A2 fractures.