The objective of this study was to determine the diagnostic accuracy of panoramic radiography and magnetic resonance imaging (MRI) for detection of signs of temporomandibular joint (TMJ) degenerative joint disease (DJD). Panoramic radiography and bilateral MRI and computed tomography (CT) of the TMJs were performed for 705 subjects. Three calibrated board-certified radiologists who were blinded to the clinical findings interpreted all images. The diagnoses of DJD established using the panoramic radiographs and MRIs were compared to the reference standard diagnoses derived from the CTs. DJD was defined as the presence of at least 1 of the following 4 signs: a subcortical cyst, surface erosion, osteophyte formation, or generalized sclerosis. The target values for sensitivity and specificity were 70% or greater and 95% or greater, respectively. Compared to the reference standard CTs, the panoramic radiographs had the following sensitivity and specificity values: subcortical cysts, 14% and 100%, respectively; erosion, 20% and 100%, respectively; osteophytes, 12% and 100%, respectively; and sclerosis, 33% and 100%, respectively. The MRIs achieved the following sensitivity and specificity values: subcortical cysts, 32% and 100% respectively; erosion, 35% and 99% respectively; osteophytes, 71% and 98%, respectively; and sclerosis, 50% and 100%, respectively. The radiologists' interexaminer reliability was slight (kappa = 0.16) when using panoramic radiographs, moderate (kappa = 0.47) when using MRIs, and substantial when using CTs (kappa = 0.71) for diagnosis of signs of DJD. Panoramic radiographs and MRIs had below-target sensitivity but above-target specificity in detecting all CT-depicted signs of DJD with the exception of osteophytes, for which MRIs demonstrated adequate diagnostic accuracy. Use of CT for diagnosis of TMJ DJD is recommended to avoid the false-negative findings that can occur if panoramic radiographs and MRIs are used.