This study examined the major job functions and knowledge domains required for effective rehabilitation counseling practice in today's rapidly changing practice environment to revise and update the test specifications for the Commission on Rehabilitation Counselor Certification examination. This report describes the methodology used in this nationwide study, the primary research questions addressed, the study's principal findings and recommendations, including the new set of test specifications that will guide future versions of the Certified Rehabilitation Counselor Examination. The results of this study provide empirical support for the description of the knowledge base underlying the practice of rehabilitation counseling and contributes further empirical evidence in relation to the content and construct validity of the knowledge domains identified in this replication and extension of the most recent study completed in 2006. (Contains 3 tables.)