Despite the high union rate of femoral shaft fractures treated with intramedullary nailing (90% to 100%), the annual incidence of femoral shaft nonunion ranges from 2% to 6%. Although less common than tibial nonunions, femoral shaft nonunions remain a clinical problem in orthopaedic surgery. Proper treatment begins with appropriate diagnosis, workup, and identification of risk factors followed by a multidisciplinary approach to treatment. This article provides current evidence-based guidance for providers on the diagnosis and management of femoral shaft nonunions.