The purposes of this study were to compare psychological profiles, to investigate the differences in the clinical characteristics, and to compare treatment outcomes between myogenous pain and arthrogenous pain subgroups of temporomandibular disorder (TMD) based on Research Diagnostic Criteria for Temporomandibular disorders (RDC/TMD). Two hundred and fifty two patients diagnosed as TMD were divided into three groups based on the RDC/TMD axis I diagnostic guidelines; myogenous pain group, arthrogenous pain group, and mixed pain (both myogenous pain and arthrogenous pain) group. RDC/TMD history questionnaire was administered to each patient and depression, somatization, jaw disability, pain intensity, disability days, and graded chronic pain scale were analyzed. Bruxism, clenching, insomnia, headache, and unilateral chewing were assessed in a standardized TMD dysfunction questionnaire and the duration of onset, chronicity of pain, treatment period, the effectiveness of the treatment, and improvement of symptoms also analyzed. Myogenous pain group had higher depression (p=0.002), and somatization scales (p<0.001) than the arthrogenous pain group. Mixed pain group showed higher pain intensity (p=0.008), disability days (p<0.001), graded chronic pain scale (p=0.005), somatization (p<0.001), and depression scores (p=0.002) than the arthrogenous pain group. Jaw disability did not show any significant differences among the three groups (p=0.058). Arthrogenous pain group reported more limitation of mouth opening than myogenous pain group (p=0.007). Duration of onset showed that the arthrogenous pain group had lowest prevalence of chronicity among three groups (p=0.002). Mixed pain group patients showed lowest symptom improvements among three groups (p=0.007). Multiple linear regression analysis results showed that the treatment effectiveness was significantly associated with somatization score (${eta}$=-0.251, p=0.03).