Atherosclerosis is the deposition of plaques containing cholesterol and lipids in arterial walls. Atherosclerosis causes cardiovascular disease that lead to heart attacks and stroke. Mortality from these diseases is the leading cause of death in the U.S. Atherogenisis starts with the uptake of oxidized LDL by endothelial macrophages, the accumulation of foam cells in the intima of the artery and the formation of fatty streaks. Research indicates that consumption of flavonoids in foods and beverages may decrease the risk of atherosclerosis. In vitro and in vivo experiments with flavonoids demonstrate that flavonoids are dietary antioxidants and inhibit LDL oxidation, inhibit platelet aggregation and adhesion, inhibit enzymes involved in lipid and lipoprotein metabolism that affect the immune response to oxidized LDL and their uptake by endothelial macrophages, may induce endothelium-dependent vassorelaxation, and may increase reverse cholesterol transport and decrease total and LDL cholesterol. Cranberries contain both hydroxycinnamic acids and flavonoids. The cranberry flavonoids belong to three groups: anthocyanins, flavonols, and proanthocyanidins. This article reviews the literature on the effects of flavonoids on atherosclerosis with an emphasis on the potential effects of the flavonols and proanthocyanidins in cranberries.