 Cellular senescence is a state of stable cell cycle arrest that occurs in response to damage or stress, and is associated with aging. It is characterized by the expression of specific genetic markers, which can be detected in various tissues and organs throughout life. Senescent cells accumulate in multiple organs during aging, contributing to tissue dysfunction and giving rise to pathological manifestations such as cancer. Recent studies have shown that targeting senescent cells could be beneficial in treating diseases related to aging, such as cancer and neurodegenerative diseases. Additionally, in vivo, identification of senescent cells has significant potential for early diagnosis of multiple pathologies. This article was authored by Marta Pois-Ribs, Estella Gonzalez-Gwalder, Gary J. Doherty, and others.