Aims: To investigate the prevalence of suicidal ideation (SI), depression, and anxiety in patients with a chronic temporomandibular disorder (TMD). Methods: The sample consisted of 1,241 consecutive patients diagnosed with muscle or joint pain, consistent with the Research Diagnostic Criteria for TMD (RDC/TMD), and assigned to one of three groups: Muscle pain (MM) group, joint pain (TMJ) group, and Mixed group. Variables of interest were specific demographics and psychometrics derived from the Symptom Checklist 90-Revised (SCL-90-R): three SI-related items, depression, anxiety, and Global Symptom Index score. Group comparisons were performed with χ2 tests and t tests; the level of significance was set at α = .05. Results: The mean (± standard deviation) age for the whole sample was 35.76 ± 12.6 years; 88.3% were women. The overall prevalence of SI items from the SCL-90-R was 8.4% for "thoughts of ending your life," 28.5% for "feeling hopeless about the future," and 20.5% for "having thoughts of death and dying." The overall prevalence of depression was 30.4% and overall prevalence of anxiety was 28.9%. Patients in the MM group reported the highest prevalence of SI. Patients in the MM group were significantly more likely to be depressed and anxious compared to patients in the TMJ (P .0001) and Mixed groups (P .0001). Conclusion: Elevated levels of SI, depression, and anxiety were reported in a chronic TMD population, especially in those with chronic muscle pain, compared to the general population. These findings emphasize the need for screening for suicidality and other comorbidities in TMD patients suffering from chronic pain. Keywords: anxiety, depression, prevalence, suicidal ideation, TMD