Temporomandibular disorders (TMD) have a strong gender predilection with a female to male sex ratio of 1.5-2:1 in the general population and 8-9:1 among patients presenting for treatment in tertiary orofacial pain centers. The purpose of the present study was to evaluate gender differences in the clinical presentation and the specific diagnoses of TMD patients, using the Research Diagnostic Criteria for TMD (RDC/TMD). Forty male and 119 female TMD patients were examined according to RDC/TMD. Participants rated their facial pain, reported associated symptoms and noxious masticatory habits. Data were analyzed by t-test and chi-square test. There were no significant differences in education level, pain intensity, jaw stiffness upon awakening, uncomfortable bite awareness, or maximum assisted opening between male and female patients. Female patients were significantly younger (p=0.001) and reported nocturnal clenching/grinding more frequently (p<0.05) than male patients. The female group had smaller painless and maximum unassisted mouth opening (p<0.05), and greater pain upon palpation of the masticatory muscles, the neck muscles, and the right temporomandibular joint (p< 0.05). In addition, TMD females exhibited fewer joint noises (p<0.05) and showed a significantly higher prevalence in RDC group I (muscle disorders) diagnoses than TMD males (p=0.001). Higher pain upon palpation and more pronounced limitation in painless and maximum unassisted mouth opening among female patients indicate a greater severity of TMD among women, which may in part explain the prominent female predominance in clinical TMD populations. In addition, the higher rate of muscle disorders in women with TMD is consistent with reports of greater excitability of central nociceptive pathways in females. Such hyperexcitability could result from microtrauma due to prolonged clenching or grinding, and might lead to persistent pain in the absence of objective peripheral pathology, such as disk displacement or osteoarthritis.