This study examined the theoretical beliefs and practice of a middle school mathematics teacher. The teacher completed formal and informal interviews and a survey that identified his beliefs about teaching, what he thought was important for his students to learn, and what he believed was the teacher's role in the classroom. The researcher conducted three classroom observations over 2 weeks. A group of 31 of the teacher's students completed a survey that was based on the teacher's answers to his survey. Data analysis indicated that the teacher's practice was closely aligned with his theoretical beliefs. The teacher was practical in his concept of his role as teacher and very technical in terms of classroom management. He had a practical orientation to teaching, with a genuine concern for students' ability to understand mathematics, not just learn it. Despite the fact that the teacher's practice was closely aligned with his beliefs, organizational and personal constraints sometimes caused him to teach in ways that were not consistent with his beliefs. (SM)