Telomeres and mitochondria are known to deteriorate over time. Telomere shortening is associated with aging, early senescence, and premature cell death. Mitochondrial dysfunction produces indiscriminate amounts of reactive oxygen species that may lead to oxidative damage to cellular constituents, including telomeric DNA, causing telomere shortening. In fact, primary mitochondrial dysfunction (for example respiratory chain disorders) and secondary mitochondrial dysfunction (such as metabolic diseases, neurodegenerative diseases, cardiovascular diseases, and mood disorders, among others) have been shown to have shorter telomeres than healthy individuals. Drawing a mechanistic connection between telomere function and mitochondria biology will provide a broader perspective for understanding the pathophysiology of diseases and their relation to the aging process, and may provide opportunities for new possible treatments.