Cardiovascular disease (CVD) is the leading cause of death worldwide. CVD is causally related to "classical" risk factors such as elevated blood pressure, cholesterol, or glucose level and smoking. A causal role in the development of CVD is also suggested for numerous other factors, including an elevated plasma homocysteine concentration. Variation of homocysteinaemia is mainly due to genetic mutations and/or vitamin deficiency. The homocysteine concentration can be lowered with folate. Vitamin supplementation has thus been proposed in individuals with hyperhomocysteinaemia in order to reduce their CVD risk. On the other hand, population-based studies show little or no association between moderate hyperhomocysteinaemia and CVD risk. Nor has any randomised clinical trial clearly proven the efficacy of lowering the homocysteine concentration as a means of lowering the incidence of CVD. Hence at present it is inappropriate to recommend screening and treatment of hyperhomocysteinaemia in asymptomatic persons with or without other CVD risk. Until new evidence is available, clinicians should focus on better control of the "classical" risk factors for CVD.