Previous studies have demonstrated an association of osteopenia/osteoporosis with idiopathic benign paroxysmal positional vertigo (BPPV). Since vitamin D takes part in the regulation of calcium and phosphorus found in the body and plays an important role in maintaining proper bone structure, decreased bone mineral density in patients with BPPV may be related to decreased serum vitamin D. We measured the serum levels of 25-hydroxyvitamin D in 100 patients (63 women and 37 men, mean age ± SD = 61.8 ± 11.6) with idiopathic BPPV and compared the data with those of 192 controls (101 women and 91 men, mean age ± SD = 60.3 ± 11.3) who had lived in the same community without dizziness or imbalance during the preceding year. The selection of the controls and acquisition of clinical information were done using the data from the Fourth Korean National Health and Nutrition Examination Survey, 2008. The serum level of 25-hydroxyvitamin D was lower in the patients with BPPV than in the controls (mean ± SD = 14.4 ± 8.4 versus 19.1 ± 6.8 ng/ml, p = 0.001). Furthermore, patients with BPPV showed a higher prevalence of decreased serum vitamin D (<20 ng/ml, 80.0 vs. 60.1 %, p < 0.001) than the controls. Multiple logistic regression analyses adjusted for age, sex, body mass index, hypertension, diabetes, proteinuria, regular exercise and the existence of decreased bone mineral density demonstrated that vitamin D insufficiency (10-20 ng/ml) and deficiency (<10 ng/ml) were associated with BPPV with the odds ratios of 3.8 (95 % confidence interval = 1.51-9.38, p = 0.004) and 23.0 (95 % confidence interval = 6.88-77.05, p < 0.001). Our study demonstrated an association between idiopathic BPPV and decreased serum vitamin D. Decreased serum vitamin D may be a risk factor of BPPV.