Lipoprotein(a) (Lp[a]) can be defined as a lipoprotein particle having as a protein moiety apolipoprotein B-100 (the protein associated with low-density lipoprotein) disulfide-linked to apolipoprotein(a), the distinctive glycoprotein of Lp(a) that is homologous to plasminogen. Several forms of Lp(a) occur in the circulation. This polymorphism is related to the apolipoprotein(a) size heterogeneity that is controlled by the several alleles of the apolipoprotein(a) gene. High plasma levels of Lp(a) have been correlated with an increased risk for atherothrombotic cardiovascular disease by a mechanism that is as yet undefined. Pathogenicity may also derive from Lp(a) particles that have been modified by events believed to occur when Lp(a), after traversing the artery endothelium, reaches the intima. Aside from several promising leads, there are no universally accepted ways to lower high plasma Lp(a) levels. At this time, it is best to target efforts toward the modifiable risk factors by using appropriate diets and exercise programs and, whenever necessary, drug therapy.