BACKGROUND: Investigation into the role of vitamin D in fractures in the pediatric population has been limited despite estimates that as many as 70% of American children have inadequate vitamin D levels (measured as 25-hydroxyvitamin D, 25(OH)D). The purpose of this study was to evaluate vitamin D's role in pediatric fracture risk by comparing 25(OH)D between fractured and nonfractured cohorts. METHODS: A 12-month prospective case-control study was completed in children aged 2 to 14 years in an urban, academic hospital. Sixty fractured children requiring conscious sedation or general anesthesia for management were compared with 60 nonfractured controls. All participants and their guardians were surveyed for low bone density risk factors, and total serum 25(OH)D was measured. Statistical analysis was completed using Student t tests, chi tests, analysis of variance, and logistic regression models. RESULTS: After controlling for age and daily sun exposure, lower total serum 25(OH)D was associated with higher fracture risk (odds ratio=0.94; 95% confidence interval, 0.90-0.99; P=0.023). In the fractured cohort, 6 (10%) patients were deficient (25(OH)D<20 ng/mL) and 33 (55%) were insufficient (25(OH)D, 20 to 30 ng/mL). Of the nonfractured population, 8 (13%) were deficient and 19 (32%) were insufficient. There were more insufficient patients in the fractured than in the nonfractured cohort (odds ratio=2.99; 95% confidence interval, 1.27-7.0; P=0.037). CONCLUSIONS: Higher fracture incidence is associated with serum 25(OH)D insufficiency. Hypovitaminosis D may place the pediatric population at increased risk for fracture. Consideration should be given to routine assessment of vitamin D in fractured children. LEVEL OF EVIDENCE: Prognostic level III-prospective case-control study.