Aims: To study the relationship between generalized joint hypermobility (GJH) and temporomandibular disorders (TMD) by assessing prevalence and patient characteristics of TMD in a population of patients with maximum expression of GJH as a symptom of inherited connective tissue disease. In addition, diagnostic reliability of a series of clinical signs indicative of temporomandibular joint (TMJ) hypermobility was tested. Methods: The study sample consisted of 42 subjects with GJH, 24 with Marfan syndrome and 18 with Ehlers-Danlos syndrome. A subgroup of 27 individuals was selected by age (¡Ý 18 yrs) and was compared to 40 controls with TMD and normal peripheral joint mobility. TMD diagnoses were assigned to each subject according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Results: In the GJH sample (n = 42), 71.4% of the subjects were symptomatic for TMD. Of those, 13.3% had sought treatment. A myofascial pain diagnosis was made in 69%, disc dislocation with reduction was diagnosed in 85.7%, and TMJ arthralgia in 61.9%. Multiple TMD diagnoses were assigned in 69% of the subjects; of these, 57% had 3 or more subgroup diagnoses. Joint noises (P < .01) and recurrent TMJ dislocations (P < .01) were a frequent finding in adult GJH subjects (n = 27) compared to controls, with symptomatic GJH subjects presenting more and more prolonged dislocation events than asymptomatic subjects (P < .001). TMJ hypermobility signs were expressed significantly more often in GJH compared to controls with TMD and normal joint mobility. Conclusion: This study indicates a positive relationship between GJH and TMD. J Orofac Pain 2005;19:47¨C57