Normal somatic cells have a finite replicative capacity, and with each cell division telomeres progressively shorten, unless the telomerase enzyme is present. The bristlecone pine, Pinus longaeva, is the oldest known living eukaryotic organism, with the oldest on record turning 4770 years old in 2005. The results from our study of telomere length and telomerase activity in samples (needle, root, core) from P. longaeva with age, and in other tree species of various lifespans, support the hypothesis that both increased telomere length and telomerase activity may contribute to the increased lifespan and longevity evident in long-lived pine trees (i.e., 2000- to 5000-year lifespan) compared with medium-lived (400- to 500-year lifespan) and short-lived (100- to 200-year lifespan) pine trees, as well as in P. longaeva with age.