In this study the functional outcome of proximal femoral nailing (PFN) in patients with unstable intertrochanteric fractures is studied and outcome is assessed with Modified Harris Hip Score. A post-operative analysis of unstable intertrochanteric fractures treated with PFN is done for its functional assessment. Various national & international studies are taken into consideration and our institutional study is compared with them. Between September 2020 to March 2022, 20 patients with unstable intertrochanteric fractures of the hip joint who were operated with PFN were functionally and clinically evaluated as per the Modified Harris Hip Score. Patients who satisfied the inclusion criteria were included in the study and follow-up was done up to 9 months. Fracture pattern, operative details and post-operative complications were documented. This study of 20 patients of unstable intertrochanteric fractures fixed with PFN showed excellent results in 9 patients (45 %), good functional outcome in 6 patients (30 %) and fair functional outcome in 3 patients (15 %). 2 patients showed a poor outcome accounting for 10%. The study showed that PFN is a reliable and effective device for the treatment of unstable intertrochanteric fractures. It provides a satisfactory fixation, but success is dependent mainly on fracture type, bony architecture, operative technique, postoperative care and rehabilitation. In view of the fewer post-operative complications, early union of fracture, early weight bearing and early return to work, we concluded the PFN to be a versatile, stable and acceptable implant in fixation of unstable intertrochanteric fractures which leads to a better functional outcome.