The purpose of this case study was to describe how one band director used pedagogical content knowledge while working with beginning-band students to help them develop the skill of playing brass lip slurs. Data were generated from (1) video recordings of each class over two different weeks during the school year, (2) "think aloud" interviews in which the teacher described what educational actions and decisions the teacher was making, and (3) detailed observation notes. I used cognitive task analysis to develop a concept map illustrating components of pedagogical content knowledge the teacher used during instruction. The teacher combined content knowledge, knowledge of students, and curriculum knowledge providing examples of how pedagogical content knowledge manifests itself in teaching beginning band. Examining the teacher's pedagogical content knowledge revealed core teaching practices that may be useful for music teacher educators to understand and develop.