In this presentation, we introduce a conceptual framework for in-service professional development--the Whole Teacher approach, which attends simultaneously to the attitudes, knowledge, and practice of a teacher's growth. Putting the framework in operation, we describe a project designed to improve teachers' competence and increase children's performance in early mathematics. Utilizing a quasi-experimental design, pre- and post-measures with intervention and comparison groups have been collected. The results indicated that significant growth in children's mathematical performance favored to the intervention group. The discussion focuses on the significance of the Whole Teacher approach to teacher professional development. [For the complete proceedings, see ED584443.]