When plastic products reach the end of their useful life, most of them are discarded by open dumping, sanitary landfill, or simple litter. In order to maintain the quality of our environment, it would be highly desirable if the litter portion were readily degradable by sunlight. Whereas earlier efforts were concerned primarily with increasing the ultraviolet-stability of plastics, the emphasis in recent years has turned increasingly toward our ability to use the same understanding and skill to increase the rate of ultraviolet degradation of such materials. The purpose of the present review is to summarize the present status of our efforts in this direction.