Summary: In this report, we describe the effect of vitamin D and calcium supplementation on fracture healing in a young boy with a hypovitaminosis D who had a radius refracture. The radiographic evaluation of the callus formation shows a clear effect of vitamin D on fracture healing in absence of additional variables. Introduction: Fracture healing restores the tissue to its original physical and mechanical properties and it involves a complex multistep process that involves response to injury, intramembranous bone formation, chondrogenesis, endochondral bone formation, and bone remodeling. All this process is influenced by a variety of systemic and local factors. It is generally assumed that vitamin D plays an intimate role in healing fractures; however, very little data exists on how it does. Case Report: In this report, the authors describe the effect of vitamin D and calcium supplementation on fracture healing in a young boy with a hypovitaminosis D who had a radius refracture. Conclusions: Our case report suggests that the hypovitaminosis D is a possible cause of inadequate fracture healing and refracture in children and it shows a clear effect of vitamin D supplementation on callus formation in the absence of additional variables. © 2014 International Osteoporosis Foundation and National Osteoporosis Foundation.