Treatment of sub-trochanteric femoral fractures is a challenge to orthopaedic surgeons. High incidence of fixation failure and nonunion is due to thick cortical bone deserves special consideration of surgical treatment. Intramedullary nail by Surgical Implant Generation Network (SIGN) shows promising results in comparison to conventional fixation method because of its better strength, accuracy and surprisingly better results in infection and non-union. The aim of this study was to assess the rate and time taken for union of fractures by SIGN nail and determine peri-operative parameters. This prospective study was conducted from July 2016 to June 2018 at National Institute of Traumatology and Orthopaedic rehabilitation (NITOR) through non randomized purposive sampling. Total 31 patients, aged above 18 years irrespective of sex with closed subtrochanteric fractures were included. Patients with pathological fracture, multiple injuries were excluded from the study. Union status evaluated by Radiographic Union Score for Tibial (RUST) fracture where antero-posterior and lateral radiographs (X-ray) based assessment of healing of the four cortices done. The individual cortical scores were added to give a total score 4 being the minimum indicating fracture is definitely not healed and 12 being the maximum score indicating that the fracture is definitely healed. The mean age of the patients was 42.61±19.59 years with range 18-80 years. Majority of patients were male (68%) and most of injury (68%) due to road traffic accident with common fracture were Seinsheimer type III (51.6%). Average hospital stay period was 16.39 days and average follows up 42.39 weeks (24-48 weeks). Time taken for union was 14.16 weeks (11-28 weeks). According to RUST scores fracture union rate 93.55% with delayed union 6.45% and no nonunion. There was one patient with superficial wound infection, one unaccepted shortening and with no implant failure. This study concludes that intramedullary interlocking SIGN nail is a safe and reliable implant for the treatment of subtrochanteric femoral fractures.