Abstract: Sirtuins are a family of proteins with NAD(+)-dependent deacetylase or mono-ADP-ribosyltransferase activity. SIRT1, the mammalian ortholog most closely related to Sir2 (the first gene of this family discovered in yeast), exhibits anti-senescence activity in a wide range of mammalian cells. Here, we describe the use of an ex vivo senescence model to study SIRT1 function in primary endothelial cells isolated from the porcine aorta. The methods can be applied to the investigation of the role of SIRT1 in the development of endothelial senescence and atherosclerosis.