As we all know recently one of the major research focuses is aging and it is among the greatest known risk factors for most human diseases. Around 150,000 people who die each day across the globe, about two thirds die from age related causes. There is increasing evidence that the aging process can have adverse effects on stem cells. As stem cells age, their renewal ability deteriorates and their ability to differentiate into the various cell types is altered. Accordingly, it is suggested aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various aging-associated disorders. Understanding the role of the aging process in deterioration of stem cell function is crucial, not only in understanding the pathophysiology of aging associated disorders, but also in future development of novel effective stem cell-based therapies to treat aging associated diseases. “Effect of aging on stem cells” (URL: http://www.wjgnet.com/2220-315X/full/v7/i1/1.htm) ̶̶̶̶̶ this review article first focuses on the basis of the various aging disease-related stem cell dysfunction. It then addresses the several concepts on the potential mechanism that causes aging-related stem cell dysfunction. It also briefly discusses the current potential therapies under development for aging associated stem cell defects.