The research plan for the NCS was developed from 2005 to 2007 in collaboration among the Interagency Coordinating Committee, the NCS Advisory Committee, the NCS Program Office, Westat, the Vanguard Center principal investigators, and federal scientists. The current design of the study, however, uses a separate pilot to assess quality of scientific output, logistics, and operations and a "Main Study" to examine exposure-outcome relationships. The NCS proposed the use of a multilayered cohort approach for the Main Study, which was one of the topics for discussion at the workshop that is the subject of this publication. In the fall of 2012, NICHD requested that the Committee on National Statistics (CNSTAT) of the NRC and the IOM convene a joint workshop, to be led by CNSTAT. The workshop was to focus on issues related to the overall design (including the framework for implementation) of the NCS. The committee was provided a background paper which it used to select the challenges that were discussed at the workshop. Design of the National Children's Study: A Workshop Summary presents an overview of the workshop held on January 11, 2013. The publication includes summaries of the four sessions of the workshop, a list of participants, and the agenda.