To address shortfalls in the preparation and achievement of U.S. students in STEM fields (science, technology, engineering, and mathematics), instruction in these areas must begin in the elementary grades, as early as kindergarten (American Association of Colleges for Teacher Education, 2007; Natural Academy of Sciences, 2007; National Research Council, 2000). The urgent need for improvement in the teaching of STEM content to young children led one university in the Southeast to create a STEM-focused elementary teacher preparation program. This exemplary program--called ATOMS (Accomplished Teachers of Mathematics and Science)--is characterized by four key features: program coherence; rigor in the general education program; innovative, conceptually focused methods courses; and extensive fieldwork aligned with coursework. This article describes the features of this highly scalable program in detail, illustrated through participant reflections and contextualized in the research literature on effective teacher education programs.