A job analysis was conducted to define knowledge important for entry-level special education teachers. The results will be used to guide the development of new test content specifications for The Praxis Series Special Education: Teaching Students with Intellectual Disabilities (SpEd: ID) assessment. A draft domain was constructed from national and professional organization standards, various state standards, textbooks, and scholarly literature. A national advisory committee (NAC) of special education teachers and college faculty reviewed and modified the draft domain to reflect the knowledge they believed was important for safe and effective practice and needed at time of entry into the profession. The revised domain consisted of 74 statements clustered within five major categories: (a) Development and Characteristics of Students with Intellectual Disabilities,1 (b) Planning and Managing the Learning Environment, (c) Instruction, (d) Assessment, and (e) Foundations and Professional Responsibilities. Survey responses of 337 special education educators provided independent evidence of the importance of the domain. Respondents judged each knowledge statement on a scale ranging from 1 (not at all important) to 5 (extremely important). A total of 73 knowledge statements had mean ratings above 3.50 in the aggregate sample and for subgroups containing more than 30 respondents. The results indicate that these 73 statements may be considered appropriate for guiding the development of new test content specifications for the Praxis SpEd: ID assessment.