The striking variability in the age of onset of and the manifestation/ absence of manifestation of cardiovascular diseases is inadequately explained by conventional risk factors, but may be explained by variation in biological age. Telomere length is possibly a reliable marker of biological age, shorter telomeres reflecting more advanced age. The initial telomere length ofa person is mainly determined by genetic factors. Moreover, the telomere length shortens with each cell division, and exposition to harmful environmental factors also results in shorter telomeres. Leukocytes of patients with atherosclerosis and heart failure display remarkably shorter telomeres compared to leukocytes of healthy subjects of similar age. Conventional cardiovascular risk factors are also associated with telomere length. If telomeres are indeed causally involved in the pathogenesis of cardiovascular disease, this might provide new avenues for future preventive and therapeutic strategies.