The purpose of this study was to characterize and document change in teaching practice among teachers involved in a Math and Science Partnership professional development project. The teachers in the study were observed as they worked together in Professional Learning Communities (PLC) in the context of workshops, graduate classes, PLC meetings, mentor sessions, and in their classrooms. They were also interviewed to fill in detailed information that could not be gathered from the other observed activities. This study documents three teachers as they engaged in all aspects of the program In order to determine whether the teachers had changed relative to the elements of the framework, they were characterized as they entered the professional development project the using the PLC Inquiry Framework, and then data from all aspects of their involvement was analyzed for evidence of change. Observational data from their respective classrooms were also studied, and an attempt was made to relate changes in the teachers' orientations regarding elements of the framework to changes in their teaching practice. The PLC Inquiry Framework focuses on whether the teachers: have a conceptual rather than a procedural orientation, display intellectual integrity, seek a coherent and connected understanding, engage reflectively, use appropriate conceptual resources, and persist through problems. This was the first time that the framework was used to make claims about individual teachers, so the framework itself was evaluated for its effectiveness in this capacity. The analysis showed that the framework was an effective tool for capturing teacher change as a result of their involvement in the project. There was evidence of change in classroom practice in two of the three cases studied. Analysis across the three cases allowed me to document factors that influenced change and factors that inhibited change. It was found that activating a teacher's desire to be conceptual rather than procedural in their orientation, or their desire for coherence will initiate the inquiry process and can result in changes in classroom practice if the proper conceptual resources are available.