Description: The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD; Dworkin and LeResche, 1992) contained specifications for patient history, clinical examination procedures, instruments for assessing the person in pain, and specific diagnostic criteria for 8 types of TMD common enough to support the development of the first version of the RDC/TMD protocol. At the outset, the goal of the 1992 publication was to foster research sufficient to lead to a stronger empirically-based revision of that protocol. In the ensuing years, the International RDC/TMD Consortium was developed and incorporated into the IADR, simultaneously supporting collaborative TMD studies around the world. More recently, a large multi-site study was funded in order to specifically examine the reliability and validity of the published RDC/TMD and to recommend revisions. This symposium aims to (1) present the research and recommendations from that study, (2) present perspectives on pain and TMD from other studies, (3) foster critical discussion regarding the status and future directions of the published RDC/TMD, and (4) develop, as an outcome, a consensus paper containing specifications for the next version of the protocol, RDC/TMD v2.0. For this full-day symposium, Session 1 (morning) will be comprised of an overview on classification systems for pain disorders followed by presentations by 5 investigators from the NIDCR-funded multi-site Validity Study Group; presentations will focus on the methods and data examining the reliability and validity of the current RDC/TMD protocol and will conclude with recommendations for revisions. Session 2 (afternoon) will be comprised of presentations by other investigators who are active in RDC/TMD research, TMD research not based on the RDC/TMD, and other pain disorder research. This Symposium is aimed at all levels of investigators in that new research questions for the next cycle of RDC/TMD development are expected to emerge from the meeting.