The out-of-school time (OST) domain offers a promising resource for enriching young people's experience of science, technology, and engineering. Belief is widespread that OST programs are ideal locations in which to learn science and that youth participation may increase access to science for underrepresented groups, such as girls or minorities, and enhance the science workforce. Indeed, many afterschool programs do offer science activities. The Coalition for Science After School found that 88 percent of programs in its network offered science activities, yet most offered 40 or fewer hours of science programming per year. In this paper, the authors describe initial findings about the characteristics of these programs and their home organizations, including aspects of program design, structure, funding, staffing, and youth audience. They then discuss how organization types differ in these program aspects and draw out implications for practice. (Contains 6 figures, 2 tables and 2 notes.)