The role of vitamin D (VitD) as a significant element in the pathophysiology of gynaecological diseases has been growing in recent years, with laboratory data intersecting with clinical data in indicating the role, or possible roles, that this vitamin may play in the field of gynaecology. The production and metabolism of VitD originates from the stimulus exerted by ultraviolet rays on the skin, with the transformation of 7-dehydrocholesterol into cholecalciferol, which, in turn, is metabolised in the liver by a 25-hydroxylase. 25(OH)D is converted at the level of the kidneys by 1-alpha-hydroxylase into 1,25(OH)2D or calcitriol, the active metabolite. Again in the kidney, 1,24,25(OH)3D, which is a biologically inactive compound, is formed by 24-hydroxylase.