Chronic kidney disease (CKD) is associated with increase cardiovascular morbidity and mortality independent of traditional cardiovascular risk factors due to increased vascular calcification. Epidemiological and experimental data suggest that hypermagnesemia and magnesium supplementation reduce vascular calcification in chronic kidney disease by increasing calcium/phosphate solubility in serum, by inhibiting calcium influx into vascular smooth muscle cells (VSMC), by inhibiting intracellular pro-calcification enzymes in VSMC and by increasing activity of intracellular anti-calcification enzymes in VSMC. A trial to investigate the effect of oral magnesium supplementation on vascular calcification in subjects with CKD is currently being planned, but prior to initiating such a trial it is necessary to determine the dose of oral magnesium needed to increase intracellular magnesium and serum magnesium.