Background: There is close relationship between Vit D deficiency and hypertension. It was found that Vit D is potent inhibitor of Renin Aldosterone Angiotensin System (RAAS) which is the main mechanism responsible for development of hypertension. Aim of The Work: To assess the role of vitamin D deficiency in the development of essential hypertension and aggravation of its vascular complications. Subjects and Methods: This study was conducted on 80 individuals. Individuals were divided into two groups: Group 1: comprising 60 patients with essential hypertension. Group 2: comprising 20 healthy individuals. All individuals included in the study were submitted to: Complete history and physical examinations to evaluate exclusion criteria. Liver and renal function tests, fasting and PP blood glucose, CBC, lipid profile, serum vitamin D (25hydroxycholecalciferol), serum Ca & Ph. Doppler study on carotid artery to assess vascular complications and Echocardiography to assess ventricular mass was done. Results: There was statistically significant decrease (p value <0.05) in vitamin D in patients group in comparison to control group. There was highly statistically significant increase (p value <0.001) in intimal thickness and left ventricular mass in patients with low vitamin D level in comparison to patients with normal vitamin D level. In the patient group, 6 patients (10%) were suffering from vitamin D deficiency while 30 (50%) were suffered from vitamin D insufficiency while 24 (35%) show normal levels of vitamin D. Interestingly, intimal thickness and ventricular mass were significantly higher in patients with essential hypertension with low vitamin D than those with normal vitamin D levels. Conclusions: Vitamin D deficiency occurs in the majority of essential hypertension patients and therefore decreased serum vitamin D levels is considered an additional risk factor for cardiovascular morbidity and mortality.