Background. Previous research on temporomandibular disorders, or TMDs, has been somewhat limited, with studies having low numbers of subjects, restricting the focus to women or looking at patients already diagnosed with chronic TMD. Because early intervention is beneficial, it is important to understand the symptoms that men and women have in the acute stage of TMD. Methods. A total of 233 patients (161 women, 72 men) with acute TMD symptoms were assessed with a battery of biopsychosocial measures. Patients were diagnosed as having TMD on the basis of research diagnostic criteria, or RDC, for TMD. After six months, patients were reassessed to determine whether they continued to have pain, thus classifying them as having chronic TMD. The authors found that 153 patients (47 men, 106 women) had developed a chronic condition, while 80 patients (25 men, 55 women) no longer reported pain (nonchronic). Results. Female and male patients who developed chronic TMD differed significantly from patients who had acute symptoms that subsided. Women who developed chronic TMD exhibited significantly more psychosocial distress and impairment than women who did not develop chronic TMD, in terms of Diagnostic and Statistical Manual, Fourth Edition, or DSM-IV, diagnoses; Beck Depression Inventory, or BDI, scores; Minnesota Multiphasic Personality Inventory scores; Multidimensional Pain Inventory, or MPI, scores; and physical and psychological measures assessed with the RDC for TMD. Men who developed chronic TMD differed significantly from men who did not develop chronic TMD, in that they exhibited more impairment in terms of DSM-IV diagnoses and BDI and RDC measures. Conclusions. These findings provide evidence that significant differences exist between men and women in regard to acute TMD symptoms. Clinical Implications. The biopsychosocial differences between men and women suggest that some treatments may be more beneficial for women than for men.