Most common among the laryngeal sarcomas is the chondrosarcoma. The difficulties in differentiation between benign and malignant behavior of cartilaginous tumors are responsible for the danger of misinterpretation of chondrosarcoma as chondroma. A case of a laryngeal chondrosarcoma is presented examined by light and electron microscopy to determine if the ultrastructure of chondrosarcoma could be helpful in the correct diagnosis. The cells and their formation play a more important role than the extracellular matrix in the differentiation of tumor's behavior. As special criterias of malignancy by electron microscopy are the presence of dominant mitochondria, fat vacuoles, dilated rough endoplasmatic reticulum and the irregular shape of chondrocytes. The knowledge of the ultrastructure of chondrosarcomas may be helpful to distinguish between a benign chondroma and low-grade chondrosarcoma, especially when only small tumor biopsies are valuable.