Paraoxonase 1 (PON1) belongs to a family of enzymes with related functions, being the best studied member. PON1 is a HDL-associated protein of which function is to protect LDL particles from oxidative modifications. The status of PON1 is influenced by different genetic, life style and dietary factors. This short review is aimed to present some new aspects regarding the antioxidant properties of PON1 with emphasis on the influence exerted by different factors. Also, a special attention is paid to the relationship between PON1 and low- and high-density lipoproteins in the context of atherosclerosis which affects the endothelial cells.