Purpose: The primary objective of this study was to assess the prevalence of temporomandibular disorders (TMDs) and comorbid factors (sleep bruxism and headaches). This study was a cross-sectional population survey in the city of Maringá, state of Paraná, Brazil. Materials and Methods: Axes I and II of the Research Diagnostic Criteria for TMD (RDC/TMD) were used for assessment of TMD signs and symptoms. The population was users of the Brazilian public health system (SUS), of both sexes, between the ages of 20 and 65 years, and not seeking treatment for TMD. Results: The selected population (N = 1,643) was composed mostly of (a) women (65.9%), (b) married or single individuals (90.6%), (c) Caucasians (70.1%), (d) individuals aged 32.7 ± 10.3 years, (e) individuals earning a medium income (75.1%), and (f) those who had completed a high school education or higher (79.9%). According to the chronic pain grade classification (CPG) in the RDC/TMD Axis II, 36.2% of the population had some degree of TMD pain (CPG I to IV); however, only 5.1% had severe limitation due to pain (CPG III or IV). In the RDC/TMD Axis I diagnoses, 29.5% presented with muscle disorders (group I), 7.9% with disk displacements (group II), and 39.1% with other joint disorders (group III). Headaches were present in 67.9% and awake and sleep bruxism in 30% and 33.4% of the population, respectively. Conclusion: The prevalence of signs and symptoms of TMD was high in this population, but with low disability; however, the proportion of patients in need of treatment was much lower.