The diagnostic process for temporomandibular disorders (TMD) is complicated by the multifactorial etiology and multiplicity of clinical signs and symptoms characterizing such disorders. Several electronic instruments and radiological techniques have been proposed over the years in the attempt to integrate clinical evaluation of TMD patients. Nonetheless, literature data still suggest that TMD diagnosis should be based on a thorough clinical assessment and international classifying scheme, also rely on standardized clinical tests to categorize TMD patients. Imaging techniques should be used to gain a better insight within the temporomandibular joint, reserving magnetic resonance to the depiction of soft tissues and computerized tomography to bone structures. EMG-based devices failed to prove effective in improving the diagnostic process for TMD, since a lack of correlation between instrumental signs and patients' symptoms has been showed. The TMD diagnostic process also relies on a psychosocial assessment of patients, which can be useful to detect a psychosocial impairment that needs to be addressed at the therapeutical level.