Atherosclerosis together with its cardiovascular consequences is the most common and significant cause of death, particularly in highly developed countries. The process of atherogenesis begins as soon as in childhood and depends on classical risk factors. Atherosclerosis also results from a chronic inflammatory-immune process which takes place in the vascular walls. Furthermore, it has been known for a number of years that the development of atherosclerotic lesions is closely connected with the concentration of homocysteine in serum. Homocysteine is a sulfur amino acid originating from methionine. An increased concentration of homocysteine in blood harmfully influences blood vessels, leading to a higher risk of ischemic heart disease and stroke. Since tackling classical atherosclerosis risk factors is not efficient enough when it comes to protecting the cardiovascular system from diseases, new substances possessing anti-atherogenic properties, especially endogenous ones, are sought. Recently, researchers have paid attention to a connection between homocysteine and an endogenous tryptophan derivative, kynurenic acid. Recently, it was revealed that kynurenic acid counteracts the harmful effects of homocysteine on endothelium cells in vitro. The hypothesis assuming homocysteine-kynurenate interplay suggests the existence of a new mechanism of atherogenesis and gives us an opportunity to use this knowledge in both prevention and treatment of cardiovascular diseases.