For teachers concerned about the underrepresentation of Hispanics and Native Americans in science fields, this paper provides resource materials and instructional approaches. First, the role of ethnocentrism in determining what is included in science courses is discussed; the non-Western impact of science has been systematically ignored, it is argued, but its contributions to civilization have important implications for both minority and majority students. The remainder of the paper discusses a variety of topics, including Mayan mathematics and the Mayan calendar, the Horizon Coordinate System (used by ancient astronomers), Mesoamerican buildings and structures used for astronomical purposes, and ideas for culturally relevant student projects in astronomy, geology, botany, agriculture, nutrition, architecture and city planning, and art. Twelve figures illustrating the discussion of astronomy and time-keeping are included and a bibliography is appended. (KH)