BACKGROUND Chondrosarcoma is a tumour with a cartilaginous matrix frequently encountered in long bones and the pelvis with rare sinonasal location. METHODS We report the case of a 25-year-old patient who was referred to us for an extension work-up for sinonasal chondrosarcoma confirmed by anatomopathological examination. RESULTS Facial magnetic resonance imaging (MRI) confirmed by a CT scan showed an osteolytic tumour process of the hard palate and walls of the left maxillary sinus that was locally advanced. CONCLUSIONS The sinonasal location of a chondrosarcoma is rare. Characterized by cross-sectional imaging, confirmation was provided by histological assessment. CONCLUSIONS The sinonasal location of a chondrosarcoma is rare.A slow-growing tumour with a cartilage matrix in adults, it is revealed mainly by neurosensorial signs and mass effect in its sinonasal location.Radiological characterization includes areas with a weak signal on T1- and T2-weighted images in MRI, not enhanced by gadolinium, corresponding to the cartilage matrix.