Aims: To determine the characteristic magnetic resonance imaging (MRI) findings of synovial chondromatosis of the temporomandibular joint (TMJ). Methods: MRI was carried out in 11 cases of synovial chondromatosis of the TMJ, which had been confirmed surgically and histologically. Results: Severe bony changes were not apparent. One or more hypointensive loose bodies were seen in 7 of the 11 cases. A considerable amount of synovial fluid, often with capsular expansion, was a common finding. Conclusion: A diagnosis of synovial chondromatosis of the TMJ must be considered when the amount of synovial fluid is abnormally large and the disc position is fairly normal, as seen on closed- and open-mouth MRI of the TMJ, without any associated severe changes in disc shape or bony structure. J OROFAC PAIN 2002;16:148–153.