This document examines the education of secondary level English language learners within mainstream science classes. It provides teachers and teacher educators with an understanding of how mainstream science instruction can be designed and implemented to enhance academic achievement for these students. Research for this report included an extensive search of various databases and World Wide Web sites; analysis of the national content standards documents for science and three other core areas; site visits to a suburban high school that used a team teaching approach to working with English language learners enrolled in mainstream classes; and personal interviews with education faculty at George Washington University who are responsible for preparing preservice teachers for secondary level mainstream instruction. After an introduction, the first section discusses National Science Education Standards and the English language learner, focusing on: involving students in scientific inquiry; advocating for a less is more curriculum; teaching the language of science; making oral and written language comprehensible; teaching problem solving and learning strategies; using appropriate assessment; and using a three-tiered approach to science instruction for English language learners. The second section discusses the preparation of mainstream teachers to work with English language learner students. (Contains 38 references.) (SM)