The aim of this study was to compare union time between two different nail designs for the treatment of humeral shaft fracture, ie antegrade interlocking intramedullary nail with and without additional interlocking neutralization screws. The retrospective study included 51 patients treated with antegrade humeral intramedullary nailing between January 2015 and December 2017. The inclusion criteria of the study were proximal and middle third humeral shaft fractures. Fifty-one patients met the inclusion criteria; 23 patients were treated with antegrade intramedullary nail with additional interlocking neutralization screws through fracture site (group A) and 28 patients were treated with antegrade intramedullary nail without additional interlocking neutralization screws (group B). Medical documentation and radiographic images taken preoperatively and postoperatively