Abstract: Objective To analyze and identify the risk factors for nonunion among patients with humeral fractures undergoing surgical fxation. Methods We retrospectively collected all patients with humeral fractures undergoing surgical fxation between January 2012 and October 2016 in department of orthopaedic trauma. Twenty humeral nonunion were identifed. Each nonunion case was matched by age and sex with two controls of healed fractures (40 control patients). Results In univariate analysis, left humeral fractures, history of smoking and history of drinking, were associated with a higher risk of nonunion (P< 0.05). In multivariate analysis, side of fracture (left) (OR=4.58, P=0.03) was the independent risk factor for nonunion of humeral fracture after surgical fixation. Conclusion Left side of fracture was independent risk factor for nonunion of humeral fracture after surgical fixation. Patients who have history of smoking or drinking, and left-side fracture should be counseled about the possibility of nonunion after surgical fxation.