The Lp(a) is a low density lipoprotein produced by the liver and it seems to be related to vascular diseases. There is a large individual variability of Lp(a) in the blood levels in the different subjects. The mechanism of the Lp(a) in the pathogenesis of atherosclerosis is not completely clear. There are a lot of different hypotheses and, one of these, is based on the structural analogy of apo(a) with plasminogen. According to current knowledge, it seems that there is a strong relationship between Lp(a) levels and coronary artery disease. Instead, there are still doubts about the real relationship between Lp(a) and stroke. Furthermore, Lp(a) levels seems to be influenced by some other cardiovascular risk factors: fibrinogen, cigarette smoke, and other. Actually, the dosage of the protein is not very useful in clinical practice.