This article explores how preservice elementary teachers change their negative beliefs toward mathematics into positive ones after taking a mathematics methods course that follows the Concrete-Pictorial-Abstract (CPA) instructional method. Also explored is the relationship between those beliefs and sociomathematical authority. By administering surveys, using reflective narratives, and informally interviewing 145 preservice teachers who are preparing to work in urban classrooms during two academic years, the study investigated changes in sociomathematical beliefs and mathematical identities. Findings reveal that most of these preservice teachers changed their mathematical identities and beliefs about teaching mathematics in positive ways to be more in accordance with reform oriented practices. Implications for preservice teacher education programs are discussed.