Rational of Vitamin D (Vit.D) is responsible for the regulation of various biological activities, it has an essential role in neurohumoral regulation of the hypothalamic-pituitary-ovarian system thus Vit.D deficiency is associated with menstrual disorder. The current study aimed to check the efficacy of Vit.D in women regarding the gynecological problem. A longitudinal interventional research study was performed to collect the data from an obstetrics and gynecology outpatient clinic in Mosul City, Iraq. Fifty participants aged between 12 and 47 years were participated in the current study, from the period of 1st December 2019 to the 1st December 2020. These reproductive women have gynecological problems with Vit.D deficiency, 25 (OH) D levels (LD < 30 ng/mL). The participants received once weekly dose of 50 000 IU orally for two months. After this period of treatment, there was a significant elevation in serum Vit.D level p < 0.0000 and significant relief of their gynecological problem (irregular menstrual cycle, menorrhagia) (p < 0.000, p < 0.0000) respectively. An administration of once weekly dose of 50 000 IU orally for two months in patients with gynecological problems (irregular cycle, menorrhagia) and Vit.D deficiency could improve these gynecological problems were observed.