Introduction: Fractures of humerus are no exception. Fractures of the humeral diaphysis constitute 3% of all fractures. It is the most challenging fracture of upper limb to be treated. Severe damages can occur if fractures are not evaluated and treated properly. The humerus is enveloped by a sleeve of muscles and has rich blood supply which helps in fracture union. As the limb does not take part in weight bearing or ambulation, some amount of shortening is functionally acceptable. But rotational deformity is not tolerated well.Traditionally humerus shaft fractures have been managed with hanging cast or brace. In modern day Open reduction and internal fixation with plate osteosynthesis has been a standard treatment for fractures of the humeral diaphysis but has the disadvantage of extensive dissection and excessive periosteal stripping, increased chances of infection or nerve damage, risk of mechanical failure in osteoporotic bone in old age. Further there is a stress shielding of bone by the plate and reduced strength of union due to primary bone healing compared to the callus healing seen in biological fixation with intramedullary nailing. Intramedullary interlocking nail is a better implant biomechanically. Nails are exposed to lesser bending force and act as a load sharing and stress shielding devices.