Temporomandibular joint disorders (TMJD) are the most common chronic orofacial pain condition affecting the masticatory system in women. Approximately 80% of individuals with TMJD are female, with an onset during the reproductive years. Co-morbid conditions such as fibromyalgia and mitral valve prolapse are frequently associated with TMJD. In 2002, the NIH deemed TMJD a national priority in women's health research and funded The National Institute of Dental & Craniofacial Research's TMJ Implant Registry and Repository (NIDCR's TIRR) at the University of Minnesota to stimulate research into TMJD and TMJ implants. ) than men (n=145, 12.2% ). Twenty-nine percent of this population reported at least one co-morbid condition. 112 (n=109F, 3M) subjects reported fibromyalgia, 208 (n=196F, 12M) arthritis, 299 (n=279F, 20M) migraine, 305 (n=278F, 27M) depression, 195 (182F, 13M) anxiety disorder, 344 (n=320F, 24M) headache, 62 (n=60F, 2M) chronic fatigue syndrome, and 116 (n=109F, 7M) heart murmur/ mitral valve prolapse. Conclusions : A female predilection for TMJD ( 88% F, 12% M) and associated co-morbid conditions (> 90% Objective F for each co-morbidity) was demonstrated in this study population. Our goal is to further investigate the interrelationship between TMJD and associated co-morbidities, both clinically and on a molecular basis. Research in this area can produce new prevention and treatment strategies. Clinicians can improve patient outcomes by being alert to the fact that TMJD may occur along with co-morbid conditions or vice versa. : To quantify the subset of subjects in NIDCR's TIRR who have TMJD and the following co-morbid conditions: fibromyalgia, arthritis, migraine, depression, anxiety disorder, headache, chronic fatigue syndrome, and heart murmur/mitral valve prolapse. Methods : TMJD subjects recruited to NIDCR's TIRR (n=1189) were evaluated for co-morbid conditions through medical records in an extensive database. Both males and females were included. Results : NIDCR's TIRR population consists of more women (n=1044, 87.8%