A large-scale laboratory facility for the maintenance of several thousand gravid sea urchins (S. purpuratus) is described. Gametes of this species provide an important research resource for studies of animal development. Methods are described for culturing adult S. purpuratus for periods up to two years or more with almost no mortality after the first three to four weeks following collection. Adult females can be maintained in a fertile state in the culture system for four to six months. When spawned, gravid females living in the culture facility will routinely regenerate normal sized populations of fertile oocytes at 1 to 2-month intervals. Such females can be used repeatedly as a source of mature gametes for laboratory research. The reproductive performance of these females can be predicted approximately by the number of late vitellogenic oocytes present in their ovaries. After several months the pool of these oocytes is exhausted and no further mature oocytes can be found for a long period. We show, however, that such females are able to carry out a complete annual cycle of oogenesis if held for a long enough period of time in the culture system.