The article describes the change in teacher training from instructivist to constructivist. The author defines constructivism and discusses its two main approaches: cognitive and social constructivism. The author then compares an instructivist versus a constructivist classroom and focuses on how they are different in terms of the level of flexibility. The author describes how an in-service teachers' workshop successfully transformed. Benefits discussed include positive learning experience and the wash-back effect on pedagogy. (This article quotes theories of Piaget, Vygotsky, and Krashen.)