On October 22 and 23, 2007, the National Cancer Institute (NCI) hosted NCI Thyroid Fine Needle Aspiration (FNA) State of the Science Conference, a two-day gathering in Bethesda, Maryland. Its mission was to establish a comprehensive interdisciplinary informational dialogue dedicated to thyroid FNA. Preparations for the conference began 18 months earlier with the designation of a steering committee, the appointment of nine working committees, coordination with co-sponsoring organizations, and the establishment of a dedicated permanent web site. The function of the website was to serve as a permanent educational tool for health care practitioners and patients alike, as well as to foster on-line dialogue. Six committees were charged with preparing summary documents based on literature reviews on the following subjects: 1. Indications/Pre-FNA requirements; 2. Training and Credentialing; 3. Technique; 4. Terminology and Morphologic Criteria; 5. Ancillary Studies; and 6. Post-FNA Options for Testing and Treatment. Three additional committees were formed, one each to oversee the website, publications ensuing from the conference and the establishment of an on-line educational cytopathology atlas. Literature reviews were limited to English language publications dating back to 1995, using PubMed as the search engine, with key words determined by the committee members. The first draft of the committees' summary documents (Review and Conclusions) was posted on the web site and open for on-line forum discussion from May 1-June 30, 2007. There were several subsequent drafts and on-line discussion periods (Aug 15 – Sept. 30, 2007 and Nov. 30-Dec. 15, 2007). The documents underwent revision after each comment period prior to re-posting on the web. The two-day live conference in October, attended by 154 registrants, comprised of pathologists, endocrinologists, surgeons, and radiologists, gave the committees an in-depth opportunity to present their conclusions and debate controversial areas. This is an abridged version of the topics reviewed at the conference and the website. This is not a standards of practice guideline, nor is it endorsed as such by the National Cancer Institute.