Aging-related pathophysiology is extremely associated with altered potential of stem cells. The changes of HSCs during aging have been studied for decades prior to other tissue stem cells, and many mechanisms are reported to be involved. Recently epigenetic regulations are shed light as central to maintaining stem cell function and epigenetic dysregulation contrib- utes to the functional decline of stem cells during aging. Alterations which arise in stem cells are not only perpetuated and amplified in stem cell pool through self-renewal, but are heritably transmitted to differentiated progenies. Such alterations can be clonally expanded and establish clonal hematopoiesis already in healthy elderly, and can promote subsequent occurrence of hematopoietic diseases. This review focuses on recent studies examining epige- netic regulation of HSCs in aging.