Mitochondria are key organelles in eukaryotic cells principally responsible for multiple cellular functions. Mitochondria play an important role in programmed cell death and regulate a multitude of different metabolic and signaling pathways. The primary function of mitochondria is to produce ATP through the process of oxidative phosphorylation, which is conducted by the four RC complexes (complexes I–IV) and the ATP synthase (complex V), all located in the inner mitochondrial membrane. Leukoplakia was most recently defined as a potentially malignant disorder with recognizable white plaques of questionable risk having excluded (other) known diseases or disorders that carry no increased risk for cancer. Aging is thought to be a degenerative process caused by accumulated damage that leads to cellular dysfunction, tissue failure, and death. A decline in mitochondrial function plays a key role in the aging process and increases the incidence of age-related disorders. We study the present state of our knowledge regarding the role of mtDNA copy number change in bodily fluids (saliva) of leukoplakia subjects in aging, We describe here a rapid, simple and accurate quantitative real-time PCR method for direct synchronized analysis of mitochondrial (mtDNA) DNA in saliva samples by using tag man probe and primers.