There is a need for effective professional development to build the skills needed to teach the Common Core State Math Standards (CCSMS) and the Standards of Mathematical Practices (SMP). The purpose of this study was to explore teachers' perspective of the SMP, the implementation process teachers were using for these practices, how they were transforming their teaching practices to match these new requirements and the role professional development (PD) played in this process. Qualitative data was gathered through teacher interviews. Analysis of the collected data uncovered common themes, including positive implementation perspectives and implementation expectations, challenges and concerns. Participants had strong positive feelings regarding the changes the CCSMS and SMP brought to education. They were excited because, even in the early stages of using some of the SMP, they saw positive results with students' mathematical thinking. Teachers also expressed concern with their lack of experience and knowledge of these standards, and the challenges some students were having with these new standards. When it came to PD, participants indicated a need for diverse opportunities to expand their skills regarding using the CCSMS and the SMP in their teaching. These participants felt that PD needed to address their needs based on their level of knowledge and skills.