Both genetic (intrinsic) and environmental (extrinsic) factors contribute to the phenotypic changes in cutaneous aging. However, only recently have the underlying molecular mechanisms involved in these changes been elucidated. DNA damage to both genomic and mitochondria) DNA and subsequent DNA repair contribute greatly to age-associated skin changes and carcinogenesis. Better understanding of these intricate, interwoven mechanisms involved in DNA damage and repair might help to develop new strategies in preventing and treating changes of intrinsic skin aging and photoaging, improving skin appearance and reducing the risk of skin cancer.