We reviewed the etiology and molecular mechanisms of photoaging, emphasizing the dominant role of ultraviolet-B in solar light. An epidemiological study demonstrated the close relationship between skin photo-type and wrinkle formation. In addition, we described the possible roles of prevention by an antioxidant protein of metallothionein and NF-κB decoy oligonucleotides in photocarcinogenesis. They have different action modes in keratinocyte apoptosis. Finally, we discussed the necessity of photoaging itself, including deep wrinkles and pigmented spots in exposed areas, for sun-protection.