Cart ilaginous tumors of the larynx are extremely rare neoplasms that account for approximately one per cent of all tumors of this organ. Less than 0.1% correspond to chondrosarcomas. Chondroma and low-grade chondrosarcoma are the most common, 70-75% of these tumors arise on the endolaryngeal surface of the posterior lamina of the cricoid cartilage. The diagnosis of laryngeal chondrosarcoma is likely to be missed because of its infrequent occurrence and its indolent pattern of growth. The clinical presentation is varied and directly dependent on size and location of tumor: stridor, hoarseness, dyspnea or neck mass are commonly presented signs. The objective of this study was to show an unusual case of laryngeal chondrosarcoma originating from thyroid cartilage, discussing its clinical presentation, diagnosis, treatment and prognosis. Rev Bras Otorrinolaringol. V.70, n.6, 823-6, nov./dec. 2004