Teachers are often disillusioned because most of the professional development that they receive is inadequate (Chappuis, Chappuis, & Stiggins, 2009; Borko, 2004). With that in mind, reform efforts have placed attentive measures on the classroom and the way teachers can improve their instructional practices. The purpose of this study was to explore biology and chemistry teachers' and facilitators' perceptions of the Alabama Science in Motion (ASIM) professional development experience. Furthermore, the researcher conducted this study to determine whether or not ASIM had an impact on teachers' classroom instruction. The results of this study were significant in that it allows for policy makers to analyze the effect that the ASIM experience has on reforming and restructuring science education. A mixed-method research design was utilized. Data was gathered from teachers and facilitators via survey and focus group interview responses. The population consisted of teachers who were trained with ASIM modules and facilitators who trained teachers in the area of biology and chemistry. A statistical data analysis was employed using the Pearson r correlation coefficient test (Pearson r). The results of this study revealed that effective professional development has an impact on teachers' classroom instruction. Teachers and facilitators believed that ASIM made them more effective as a teacher and contributed strongly to their students' understanding of biology and chemistry. Moreover, teachers and facilitators believed that the ASIM modules assisted them in the implementation of the standards on the Alabama Course of Study.