Epigenetics, the study of heritable alterations in gene expression without changes to the DNA sequence, plays a pivotal role in understanding the complex processes of aging and cancer. This manuscript delves into the intricate world of epigenetics, exploring how it influences the pathophysiology of aging and aging-related diseases, with a particular focus on cancer. We discuss the mechanisms of epigenetic regulation, the interplay between genetic and epigenetic alterations, and the potential implications for diagnosis and drug discovery.