Vitamin D is essential for optimal bone health. Stress fracture is an overuse injury often occurring in active populations. Study results indicate an association exists between vitamin D status and the risk of stress fracture, and one intervention trial demonstrated a reduction in stress fractures in women consuming supplemental vitamin D and calcium. A recent study found that two polymorphisms in the vitamin D receptor (VDR), Fok1 and Bsm1, may increase the risk of stress fracture. Although further study is required, screening for VDR polymorphisms may become a tool for identifying individuals at increased risk of stress fracture during physical training.