The process of aging is one of the most complex and intruguing biological phenomenons. Aging is a genetically regulated process in which the organism’s maximum lifespan potential is pre-determined, while the rate of aging is influenced by environmental factors and lifestyle. Considering the complexity of mechanisms involved in the regulation of aging process, up to this date there isn’t a major, unifying theory which could explain them. As genetic/epigenetic and environmental factors both inevitably influence the aging process, here we present a review on the genetic and epigenetic regulation of the most important molecular and cellular mechanisms involved in the process of aging. Based on the studies on oxidative stress, metabolism, genome stability, epigenetic modifications and cellular senescence in animal models and humans, we give an overview of key genetic and molecular pathways related to aging. As most of genetic manipulations which influence the aging process also affect reproduction, we discuss aging in humans as a post-reproductive genetically determined process. After the age of reproductive success, aging countinously progresses which clinically coincides with the onset of most chronic diseases, cancers and dementions. As evolution shapes the genomes for reproductive success and not for post-reproductive survival, aging could be defined as a protective mechanism which ensures the preservation and progress of species through the modification, trasnmission and improvement of genetic material.