The main cause of mortality and morbidity in Europe and United States are cardiovascular diseases. Besides well known atherogenic risk factors there has recently been a lot of attention paid to homocysteine. It is a sulfur aminoacid which is the demethylation product of methionine. Many facts support the role of this agent in development of arteriosclerosis and its sequelle. The relation of hyperhomocysteinemia with vascular complications, therapeutic options and potential atherogenic mechanisms are discussed in this paper. Special attention was paid to chronic renal failure patients.