The goal of this study is to evaluate surgical treatment outcomes of fracture shaft humerus by using intramedullary interlocking nail. Fifteen patients (ages ranged from 51 to 70 with an average age of 64.20 ± 6.338 years, (10 males and 5 females) with shaft humeral fractures from Beni-Suef University and General hospitals during the period from December 2012 to June 2014. The selected participants were treated with intramedullary interlocking nail. Patients were followed up for a mean of 9 (range 6-12) months. The mean length of hospital stay was 3 (range 1-5) days. All the fractures united radiographically after a mean of 14 (range, 12-20) weeks. Conclusion: That the majority of humeral shaft fractures can be treated safely and effectively by non-operative methods. However, for the subset of patients requiring surgical treatment, intramedullary nailing provides predictable means of achieving fracture stabilization and ultimate healing. Poor outcome in intramedullary interlocking nailing is attributable to rotator cuff tear and shoulder impingement and lack of expertise of surgeon.