Temporomandibular disorder (TMD) is a common name for a series of pathologic conditions with similar signs and symptoms, which can lead to a disturbed and altered function of the stomatognathic system. Most of these conditions are of a multifactorial etiology, which can pose difficulties in obtaining a precise and accurate diagnosis. However, TMD is an ever more common and serious problem in contemporary dental practice and at general medical offices, so a more systematic approach in its diagnosis including data collection and interpretation is necessary. Accordingly, accurate diagnosis of TMD requires proper identification and classification of the dysfunction, as well as recognition of the mechanism and origin of pain occurrence.