Critical review of the available evidence indicates that a relationship exists between sufficient vitamin D status and stress fractures, although genetic and environmental factors are involved as well. Patients at high risk for stress fracture should be educated on protective training techniques and the potential benefits of supplementation with combined calcium and vitamin D, particularly if increased exercise is planned during winter or spring months, when vitamin D stores are at their lowest. The amount of vitamin D intake required is highly variable depending on many factors including sun exposure, and therefore many recommendations have been made for daily vitamin D intake requirements. While the Institute of Medicine guidelines suggest that 600 to 800 IU of vitamin D are required for adequate bone health in most adults, we recommend that most patients receive 800 to 1,000 IU and perhaps as high as 2,000 IU of vitamin D3 as outlined by the previously mentioned review article since vitamin D is a safe treatment with a high therapeutic index. Also, at least 1,000 mg of calcium per day is required for optimal bone health and 1,200 mg may be needed in certain populations. Orthopaedists should consider prescribing vitamin D and calcium prophylactically in high-risk patients. In patients in whom deficiency is a concern, serum 25(OH)D level is the appropriate screening test, with therapeutic goals for bone health being at least 50 nmol/L (20 ng/mL) and may be as high as 90 to 100 nmol/L (36 to 40 ng/mL).