Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Recently vitamin D deficiency has been identified as a potential risk factor for many diseases not traditionally associated with vitamin D, such as cancer and CVD. This review discusses the evidence suggesting an association between low 25-hydroxyvitamin D levels and CVD and the possible mechanisms mediating it. Vitamin D deficiency has been associated with CVD risk factors such as hypertension and diabetes mellitus, with markers of subclinical atherosclerosis such as intima-media thickness and coronary calcification as well as with cardiovascular events such as myocardial infarction and stroke as well as congestive heart failure. It could be suggested that vitamin D deficiency contributes to the development of CVD through its association with risk factors, such as diabetes and hypertension. However, direct effects of vitamin D on the cardiovascular system may also be involved. Vitamin D receptors are expressed in a variety of tissues, including cardiomyocytes, vascular smooth muscle cells and endothelial cells and vitamin D has been shown to affect inflammation and cell proliferation and differentiation. While much evidence supports a potential antiatherosclerotic effect of vitamin D, prospective, placebo-controlled randomized as well as mechanistic studies are needed to confirm this association. Since vitamin D deficiency is easy to screen for and treat, the confirmation of such an association could have important implications for both, patient care and health policy.