The objective of this prospective study showing the result of fixation of fracture shaft tibia in adults by intramedullary interlocking nail tibia. Thirty patients with fracture shaft tibia simple & compound fracture type 1 & 2 Gustilo-Anderson Classification. Surgical protocol of fixation of fracture shaft tibia in adults by intramedullary interlocking nail tibia Regarding union, alignment & functional results using Olerud functional scoring system. According to Olerud functional scoring system 17 patients had excellent overall functional results, 10 had good results, 2 had fair results only one patient had poor result on account of her old age and poor health condition. Intramedullary nailing is the best option. Solid core nails are associated with the lowest rate of infection. Intramedullary nailing is the current most popular form of surgical treatment. It has many advantages include: Indicated in cases of segmental and comminuted fractures shaft tibia, saving fracture hematoma, early weight baring, minimal incision, less blood loss.