The authors present a rare patient of right synovial chondromatosis (SC) of the temporomandibular joint in which diagnosis was late and delay led to SC extension to the cranial base. Synovial chondromatosis is a rare benign disorder characterized by multiple cartilaginous free-floating nodules originated from the synovial membrane of large articular joints of the body. Differential diagnosis is with neoplasm and radical surgical removal is essential. The patient came to the authors’ observation complaining about long-lasting temporomandibular joint dysfunction. The patient already underwent either functional or medical therapy in times without any improvement. Clinical examination showed limited mouth opening and swelling of the right preauricolar region with no signs of facial nerve palsy and without paresthesia or hearing loss. No history of recent trauma was recorded. Magnetic resonance imaging showed a mucous-like hyperintense mass with small hypointense spots inside. A preoperative computed tomography scan was performed and showed a mass extending from the superior aspect of the temporomandibular joint to the glenoid fossa, which was partially eroded. The patient underwent either open joint surgery or arthroscopy of the superior joint space and a large number of chondrocytes were removed. No complications were recorded postoperatively and the patient completely recovered after 6 months. Histology confirmed the diagnosis of synovial condromatosys of the right temporomandibular joint.