Epidemiological evidence, linking moderate elevations in homocysteine to cardiovascular events, is compelling but inconclusive. Folic acid and vitamin B12 have been used to reduce homocysteine levels and treat hyperhomocysteinemia. The clinical benefits will be established over the next 5 years as data from randomized trials becomes available. In this paper, two cost-effectiveness analyses examining 'treating all' versus 'screen and treat' are reviewed. Some experts are endorsing screening high-risk patients for elevated homocysteine but most professional societies recommend waiting until more evidence is available from peer-reviewed publications of the results of clinical trials before endorsing population-wide screening or treatment.