Aims: To characterize the level of impairment of oral health-related quality of life (OHRQoL) in a temporomandibular disorder (TMD) patient population. Methods: OHRQoL was measured using the German version of the Oral Health Impact Profile (OHIP-G) in a consecutive sample of 416 patients seeking treatment for their complaints in the masticatory muscles and temporomandibular joints and with at least 1 diagnosis according to the German version of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The level of impairment of OHRQoL was characterized by the OHIP summary score mean and its 95% confidence interval. OHRQoL was described for each of the 8 RDC/TMD diagnoses (Axis I) and the RDC/TMD Axis II measures (Graded Chronic Pain Scale [GCPS], jaw disability list, depression, and somatization). These findings were compared with the level of impairment of OHRQoL in the adult general population derived from a national sample (n = 2,026). Results: Among the RDC/TMD Axis I measures, all diagnoses were correlated with much higher impacts compared to the normal population (means for all diagnoses were 32.8 to 53.7 versus 15.8 in the general population). All diagnoses had a similar level of impact except for disc displacement with reduction (which had a lower impact). There were larger differences in mean OHIP-G scores among subgroups of RDC/TMD Axis II measures than among subgroups of RDC/TMD Axis I characteristics. The strongest association was with GCPS, with mean OHIP scores of 33.3 for grade I, 48.1 for grade II, 71.7 for grade III, and 88.5 for grade IV. Conclusion: OHRQoL was markedly impaired in TMD patients. The level of OHRQoL varied across diagnostic categories but more across Axis II, ie, the psychosocial axis; the variation was reflected especially in their level of graded chronic pain. Keywords: depression, Graded Chronic Pain Scale, jaw disability, Oral Health Impact Profile, oral health-related quality of life, Research Diagnostic Criteria for Temporomandibular Disorders, somatization, temporomandibular disorders