Mesenchymal chondrosarcoma (MCS), described in 1959 by Lichtenstein & Bernstein, is a very rare malignant tumour. Only 46 cases have been previously reported in the jaws. Over a period of 30 years, four chondrosarcomas of mesenchymal type (of which one has already been published in 1987 with a three-month follow up) were treated in our department. Two patients have been followed for more than 17 years, of whom one has died of an intracranial extension and the other is still alive after surgical treatment of numerous recurrences and metastases. The two others are tumour-free with a follow up of 18 months and 11 years respectively. Histological, epidemiological and clinical features and treatment of MCS are discussed relevant to the data published in the literature.