Many preservice teachers are introduced to NCTM's "Principles and Standards for School Mathematics" (2000) and practices that support those Standards as part of their teacher education programs. They often appear to accept the underlying principles, and many intend to implement this type of instruction in their own classrooms. Unfortunately, as novice teachers, they experience difficulty in putting the needed practices in place because of classroom management, lack of resources, or demands of time to prepare lessons and activities. Although a variety of compounding variables can thwart the novice teacher, this article will focus on the one that impacts all the others: classroom management. A professional development program will be described that is designed to support the beginning teachers' implementation of Standards-based instruction that is aligned with "Principles and Standards." The strategies that were used to help these beginning teachers manage their classrooms when they ventured into this type of instruction will also be discussed. (Contains 1 table.)