The assessment, diagnosis, and management of fractures, particularly fractures that exhibit delayed healing, present considerable unique challenges to both patients and physicians. Fracture healing results from a complex series of biochemical events that may produce complete restoration of the anatomic and biochemical properties of the original osseous tissue. Fracture healing requires appropriate reduction, mechanical stability, and adequate vascularity to the fracture site; compromise of one of these elements may lead to delayed healing or nonunion. The patient’s history, physical examination, and findings based on radiographs or other imaging modalities allow for assessment and characterization of the progression of healing. If nonunion is recognized, it is important for the clinician to understand the current treatment options that are available to optimize healing. Physical stimulation therapies include electromagnetic stimulation and low-intensity pulsed ultrasonography. Osteogenic factors used locally to promote fracture healing include autologous bone marrow and peptide signaling molecules such as platelet-derived growth factors, fibroblast growth factors, and bone morphogenetic proteins. Systemic biological protein such as parathyroid hormone and factors that target the Wnt family of signaling molecules offers promising data regarding its abilities to promote healing. Large segmental defects must be managed depending on the type and severity of the injury and may require treatment with bone grafts, induced membrane techniques, acute shortening, or distraction osteogenesis. A systematic approach in evaluating fracture union and an understanding of the modern methods to promote fracture healing will allow clinicians to significantly improve the treatment of patients with these injuries.