Atherosclerosis can be defined as a disease process that occurs when the influx and deposition of cholesterol into the arterial wall exceed the egress of cholesterol from the arterial wall. This process is characterized by early deposition of cholesterol in and around arterial wall cells. The cholesterol is derived from certain types of plasma lipoproteins. While these lipoproteins deliver cholesterol to the arterial wall cells, other types of plasma lipoproteins may be capable of removing cholesterol from the cells and transporting the cholesterol to the liver for excretion from the body. As the involvement of various lipoproteins in cholesterol influx and egress is better understood, the mechanisms whereby accelerated atherosclerosis occurs are more clearly defined. This review considers recent findings related to identification of lipoproteins capable of delivering cholesterol to cells of the arterial wall and those capable of removing cholesterol from these cells for transport to the liver.