In June 2010, the National Governors Association Center for Best Practices (NGA Center) and the Council of Chief State School Offices (CCSSO) released the Common Core State Standards. The stated aim of the Common Core standards is to define the knowledge and skills students should achieve in order to graduate from high school ready to succeed in a wide range of postsecondary educational settings (Common Core State Standards Initiative, 2010a). As of October 2011, 44 states and the District of Columbia had officially adopted the standards. This widespread potential implementation of the Common Core standards has led to interest by states and national organizations regarding the relationship between these new standards and existing systems of standards. Are Common Core standards aligned with the standards states and others have developed over many years? Are they as challenging? Do they cover the same topic areas with the same emphases? To help answer these questions, the Educational Policy Improvement Center (EPIC), designed and conducted this study to determine the extent of correspondence (alignment) between the exit level Common Core standards and each of five sets of existing standards, were explicitly written at the college readiness level, or represented a rigorous instructional program focused on college readiness. The purpose was to see if the Common Core standards cover similar content, how broadly they cover the comparison standards, and how the cognitive challenge level of aligned content matches up. While additional analyses at the individual state level are needed, the overall findings from this study suggest a general level of agreement between the Common Core standards and the comparison standards regarding what is important for high school students to know and be able to do and the cognitive level at which they need to demonstrate key skills in English language arts and mathematics in order to be ready for college and careers. Appended are: (1) Description of the Depth of Knowledge Calculation; (2) Common Core Standards; (3) Results by Individual Comparison Standards; and (4) Alignment Matches for Common Core Content-Specific Areas. (Contains 43 figures, 45 tables and 17 footnotes.)