A number of investigators have suggested that the generic classification temporomandibular disorders (TMD) may consist of several subsets of patients. Two primary factors are to be significant in discriminating subgroups, namely, presence or absence of TM joint abnormalities and psychological characteristics such as traits, maladaptive behavioral patterns, and gross psychopathology. Few attempts, however, have been made to integrate psychosocial and behavioral parameters in order to identify a taxonomy of TMD patients and, subsequently, to examine the differentiation of subgroups on oral dysfunction/structural abnormalities (OD/SA). The primary purpose of this paper was to develop and cross-validate an empirically derived classification system of TMD patients. The first study identified three unique subgroups of TMD patients, labeled 'dysfunctional,' 'interpersonally distressed,' and 'adaptative copers.' A second study cross-validated and confirmed the uniqueness and accuracy of the taxonomy. Subsequent analyses were performed that demonstrated that these groups were not distinguishable on the basis of any measures of OD/SA. The taxonomy identified is compared and contrasted with other reported subgroups of TMD patients and the implications of this classification system for treatment of TMD patients are discussed.