Background Uterine leiomyoma (fibroids) are the commonest benign tumour of the uterus. It is a common cause of severe morbidity in the reproductive age group including excessive vagina bleeding, miscarriage, infertility and chronic pelvic pain. It is a leading cause of abdominal surgeries (myomectomy, caesarean section and hysterectomy). It has a racial predilection with higher prevalence in the blacks. Women who have uterine fibroids with a desire to preserve their reproductive potential have limited treatment options. Vitamin D regulates the cell cycle regulatory genes and modulates activities of cyclin-dependent kinases, leading to a decreased number of cells in the S phase and an accumulation of cells in the G0–G1. It has therefore been proven as an antiproliferative agent. Vitamin D acts on vitamin D receptors throughout the body including and are also in numerous quantities in the uterus. It has been postulated that vitamin D has a role in the aetio-pathology of uterine fibroid. Presently, there is limited effective long term medicinal treatment for uterine fibroids however, there is a growing interest in the role of vitamin D in the development of uterine fibroid and whether the administration of vitamin D supplement has a protective effect in its development Objectives To determine the serum vitamin D level in women who has uterine fibroid and those who don’t and to determine whether serum vitamin D level correlated with the volume of fibroid. Methods All women in the reproductive age group (15 to 49 years) referred to the gynaecology clinic of the Department of Obstetrics and Gynaecology of the Lagos University Teaching Hospital who did a pelvic ultrasound scan were considered for recruitment into the study Group I if they were diagnosed with at least 1 uterine leiomyoma with a mean diameter ≥10 mm and group II (control group) if there were unremarkable finding (i.e, no fibroid found or if the mean diameter of uterine fibroid found was <10mm) during pelvic ultrasound scan. The serum of participating women was tested for 25-hydroxyvitamin D3 level. To prevent misdiagnoses, women were excluded if sonographic evaluation of the characteristics of the uterine fibroid was difficult, in the presence of suspected adenomyosis, uterine fibroid size less than 10mm, patients with malignancy and associated medical disorders such as hypertension, diabetes, multiple sclerosis, autoimmune disorders and coronary, hepatic, or renal diseases were excluded from the study.