Purpose To investigate the clinical, imaging and pathologic characteristics of dedifferentiated chondrosarcoma.Methods The clinical and pathological data were reviewed in 11 cases of dedifferentiated chondrosarcoma.Results Most of these patients were male (7/11). The mean age was 57.1 years.Most tumors were located in the long bone and pelvis. Imaging showed that bones were extensively destroyed.There was calcification or ossification on focus of infection. The gross specimen showed that cartilage component was located within bone and dedifferentiated sarcoma was found out of the bone.Microscopically, well differentiated chondrosarcoma and poorly differentiated sarcoma components were observed. Six patients died and the average survival time was 14 months.Conclusions Dedifferentiated chondrosarcoma is an unusual subtype of chondrosarcoma with pleomorphic alterations. Further understanding the pathologic features of the tumor is important to increase the accurancy of diagnosis.