This study assessed electronic thermography as a diagnostic alternative for evaluation of temporomandibular disorders. The study populations consisted of 50 temporomandibular joint patients having internal derangement or osteoarthrosis and 30 normal temporomandibular joint subjects. An Agema 870 thermovision unit was used for analysis. Diagnostic evaluations by expert interpreters were made using standard procedures. Thermography measurements included mean absolute temperature measurements and right-left temperature differences for five anatomic zones and four spot areas. Statistical analysis of data included both linear discriminant analysis and classification-tree analysis. Results indicated that when differentiating between abnormal and ormal temporomandibular joints using classification-tree analysis, correct classifications were made in 89% of the cases and observer diagnostic accuracy was 84%. When evaluating for specific diagnoses (eg, osteoarthrosis, internal derangement, or normal temporomandibular joint), correct classifications using classification-tree analysis were made in 73% of the cases and observer evaluation was correct in 59%. The three best temperature measures found were: (1) delta T of the zone immediately overlying the temporomandibular joint; (2) the zone temperature of the half-face; and (3) the spot temperature anterior to the external auditory meatus. Additional studies are needed before thermographic diagnosis of craniomandibular disorders is accepted clinically.