Aim: To assess the relationship between vitamin D level and polycystic ovary syndrome. Methods: Fifty- eight women of reproductive age 18- 40 years were divided into two groups. Group I with 25(OH)D3 deficiency, and group II with normal 25(OH)D3. Biochemical and hormonal parameters (androgen hormones, gonadotropins, and thyroid function tests) was assessed. Weight, height, Body mass index (BMI) and waist circumference (WC) measurements were recorded. Result: The mean age in group I patients was 28.4 years and in group II was 29 years. The mean waist circumference (WC) was 92.4 cm in group I and 83.7 cm in group II. The mean BMI was 29.1 kg/m2 in group I and 31.4 kg/m2 in group II. The difference was significant (P< 0.05). The mean fasting glucose level was 93.2 mg/dl in group I and 81.4 mg/dl in group II. HOMA- IR was 3.8 in group I and 3.2 in group II. Serum calcium was 8.4 mg/dl in group I and 9.1 mg/dl in group II. Triglyceride was 143.5 mg/dl in group I and 137.4 mg/dl in group II. LDL-C was 145.2 mg/dl in group I and 144.9 mg/dl in group II. HDL-C was 40.1 mg/dl in group I and 49.2 mg/dl in group II. The difference was significant (P< 0.05). The mean FSH (mlU/mL) was 6.8 and 6.4 in group I and group II respectively. The mean LH (mlU/mL) was 8.4 and 9.6, serum testosterone (ng/ml) was 7.5 and 5.2, PRL (ng/ml) was 23.1 and 15.4, DHEA-S (ng/ml) was 712.4 and 532.6, TSH (µIU/L) was 2.7 and 2.5 and sT4, pmol/L was 11.2 and 12.4 in group I and group II respectively. A significant difference was observed (P< 0.05). There was correlation between 25(OH)D3 levels and WC, BMI, fasting glucose, HOMA- IR, LH, serum testosterone and DHEA-S (P< 0.05). Conclusion: There was correlation between polycystic ovary syndrome and vitamin D deficiency. We suggest that vitamin D deficiency exacerbates the risk of polycystic ovary syndrome.