With the adoption of the National Common Core State Standards in Mathematics (CCSSM) in many states and the lack of understanding and strategies to implement the new standards by classroom teachers, implementing effective professional development is vital. The focus of this qualitative case study was to provide insight into elementary school teachers' perceptions of preparedness for implementing the CCSSM after a series of professional development trainings focused on teaching the CCSSM. Qualitative data were obtained from online surveys and six teacher interviews. Survey data collected from volunteers consisting of 29 elementary school teachers ranging from kindergarten through fifth grades revealed that overall, teachers felt prepared to teach the Common CCSSM based on the professional development experiences provided by the district's math coach. The six teachers who participated in semi-structured, in-depth interviews and provided additional insight into their professional development experiences also supported the survey responses related to adequate preparation for lesson planning, math problem solving, instructional strategies, and assessment. Although teachers feel adequately prepared to teach the standards, the study revealed that ongoing professional opportunities are warranted. The current findings indicated the importance of well-designed, ongoing professional development. Sufficient time was also cited as a major concern of the interview respondents. School districts and local schools need to identify training classes and resources intermittently that prepare teachers for each grading period at the elementary level. Recommendations for future research include studies that utilize a similar methodology but include teachers at the middle and high school levels. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]