Introduction: The chondromatosis of the jaw is a proliferative disease coming with a metaplastic formation of chondral nodules in the structures of the joint area. Its manifestation in the temporo mandibular joint is a rarity. The average time frame from the occurrence of the first symptoms until surgical intervention avarages two years. Patients and diagnosis: The diagnosis, the clinical procedure and the histological appraisal of two patients - female, 47 years and male, 39 years - are described. After clinical examination and MRI radiology, the surgical resection of the lesions was performed via pre-auricular approach. Results: In both cases the over 50 chondral nodules, in parts adherent to the joint structures, were of different size and shape, invariably sharply bounded and could be removed completely. There were no complications as wound infections or lesions of the facial nerve. The function of the temporo mandibular joint was fully restored: there were no lateral deviations, pain or sounds. The mouth opening was undisturbed. The pathohistological diagnosis was synovial chondromatosis respectively. Conclusion: The synovial chondromatosis takes an intermediate position between benign enchondromas and malignant chondrosarcomas. A malignant progression of the chondromatosis is observed in 5% of the cases; in 15% recurrent disease appears despite a complete removal of the initial lesion. A stringent recall system for the patients concerned is indispensable. Schlagwörter: Synoviale Chondromatose, Kiefergelenk, gutartig, Synovia