We aimed to evaluate the relationship between serum 25-hydroxy vitamin D levels and the risk of uterine fibroids in premenopausal women in Turkish population in this prospective observational cross-sectional study. Sixty-eight women with at least one uterine leiomyoma >= 10 mm were compared with 56 healthy controls. Serum 25-(OH) vitamin D-3 levels were measured by electrochemiluminescence immunoassay. The groups were similar in terms of age, BMI, gravidity and parity numbers. The mean level of 25-(OH) D3 were 7.28 +/- 4.94 ng/ml and 78% of patients (n=97) had severe vitamin D deficiency (<10 ng/mL). Vitamin D levels were significantly lower in the study group (6.54 +/- 4.66 ng/ml vs. 8.18 +/- 5.16 ng/ml, respectively; p=.009). Vitamin D levels were not correlated with size, volume, localization and number of leiomyomas. Traditional covered clothing style, low education level and being housewife were risk factors for Vitamin D deficiency. This is the first study that investigates the vitamin D levels in women with leiomyomas in Turkish population. Influence of vitamin D on uterine leiomyoma formation to may lead to new preventive strategies in the future.