Introduction: With surgical advancements and improved implants and instrumentation, nailing is the procedure of choice in subtrochanteric fractures. However, failure in achieving reduction of the multidirectional displacement of the fragments prior to passing the nail, contributes to delayed/non-unions at the fracture site leading to implant failures. In this study, we aim to analyse the factors affecting union of closed subtrochanteric fractures treated by nailing. Materials and methods: In this retrospective study, closed subtrochanteric fractures treated with cephalomedullary nailing between 2015 and 2019 were included. Demographic, surgical and radiological data were retrieved and analysed. A total of 60 cases were eligible to be included in the study. Results: Majority of patients were male (50), with a mean age of 46.07±16.40 years. Twenty-two fractures were multifragmentary having a separate butterfly fragment. In 27 patients mini-open technique was used to get the anatomical alignment and to hold reduction until fixation. Overall, the mean time for union was 7.63±5.85 months. We had nine delayed unions and eight non-unions. Varus alignment in the coronal plane of more than 8.5° was the only significant factor associated with delayed or non-union apart from loss of medial continuity. Conclusion: We recommend achieving fracture reduction with less than 8.5° of varus malalignment in the coronal plane. Varus malalignment is poorly tolerated in fractures at this region. To achieve this, we suggest having a very low threshold to minimally open the fracture site for reduction of these fractures, which does not have any negative effect on the fracture union.