Magnesium is one of the 11 most abundant elements in the human body and it is required for the action of over 300 enzymes. It is the most common intracellular, bivalent cation. It is located in quite important structures from DNA/RNA to ATP. It interacts with negatively charged ions to provide an allosteric effect and therefore plays the role of a bridge in connecting different molecules. It is mostly found in dark green vegetables, the chlorophyl complex and unprocessed cereals. The current environmental pollution and the increased consumption of refined products cause serious problems with Mg uptake. Despite considerable advances over the last decades, cardiovascular diseases exact a very high toll as the leading cause of death in Western societies. This is mainly the result of the increasing prevalence of atherosclerosis, related to the aging of the population, the increase in diabetes and obesity, unhealthy diets, sedentary lifestyle, and particularly hyperlipidemia and hypertension. Chronic kidney diseases are quite common in the population at present and are associated with serious mortality and morbidity. Our aim in this review was to investigate the effect of Mg on endothelial dysfunction, atherosclerosis and CKD.