Telomeres are repetitive nucleotide elements at the ends of chromosomes that protect chromosomes from degradation and genetic information loss. Normal diploid cells lose telomeres with each cell cycle. Telomere length, therefore, decreases over time and may predict lifespan. Accurate and consistent quantification of telomere length is important in many aspects of cell biology such as chromosomal instability, DNA repair, senescence, apoptosis, cell dysfunctions and oncogenesis. Mitochondrial DNA (mtDNA) is circular, multicopy genome DNA located in mitochondrion, a cellular organelle that plays a key role in the energy production. The capacity for energy production in a cell depends on both mtDNA integrity and copy number. Evidence suggests that telomere length and mitochondrial dysfunction are positively correlated in cellular aging and other age-related disorders such as cancer, diabetes and neurodegenerative diseases.