Although most researches into the changes in skin with age focus on the unwelcome aesthetic aspects of the aging skin, skin deterioration with age is more than a merely cosmetic problem. Although mortality from skin disease is primarily restricted to melanoma, dermatological disorders are ubiquitous in older people with a significant impact on quality of life. The structural and functional deterioration of the skin that occurs with age has numerous clinical presentations, ranging from benign but potentially excruciating disorders like pruritus to the more threatening carcinomas and melanomas.The degenerative changes that occur in the aging skin are increasingly understood at both the molecular and cellular level, facilitating a deeper understanding of the structural and functional deterioration that these changes produce.A loss of both function and structural stability in skin proceeds unavoidably as individuals age, which is the result of both intrinsic and extrinsic processes, which contribute simultaneously to a progressive loss of skin integrity. Intrinsic aging proceeds at a genetically determined pace, primarily caused by the buildup of damaging products of cellular metabolism as well as an increasing biological aging of the cells. Estrogen levels strongly influence skin integrity in women as well; falling levels in midlife, therefore, produce premature aging as compared with similarly aged men. Extrinsic insults from the environment add to the dermatological signs of aging.A deeper understanding of the physiological basis of skin aging will facilitate progress in the treatment of the unwelcome sequelae of aging skin, both cosmetic and pathogenic.