This paper on science instruction for learners with mental disabilities reviews the limited literature base in the field and provides practical information on teaching science in special settings. To assist in implementing best instructional practices in science education, the paper discusses the curricular make-up of science instruction; various instructional approaches, programs, and strategies for teaching science to special learners; and selected instructional and resource materials. The advantages and disadvantages of various approaches to teaching science are presented, discussing textbooks, process/inquiry programs, specialized programs, customized programs, and eclectic approaches. A section on instructional strategies focuses attention on: the components of a science lesson, integration of other subject and skill areas into science, specific learning strategies that can help students, safety in the science classroom, use of microcomputers, ways to make the classroom "sciency," and recommendations for acquiring requisite laboratory materials and equipment. Four tables are provided. (JDD)