<p><b>OBJECTIVE</b>To summarize the clinical, pathological and prognosis character of malignant carotid body tumor and explore its methods of diagnosis and treatment.</p><p><b>METHODS</b>The data of clinic, pathology, treatment and follow-up of nine patients with malignant carotid body tumor in Tianjin Cancer Hospital from February 1982 to June 2006 were analyzed retrospectively.</p><p><b>RESULTS</b>Four Male and five female cases were included, their average history was 6.5 years. Shamblin classification: one case was type II, eight cases were type III. All the patients were underwent ultrasonic inspection, four digital subtraction arteriography (DSA) and three magnetic resonance angiography (MRA). Seven cases were diagnosed as carotid body tumor. Five cases underwent Matas test training course. All the patients were performed wide excision of tumor and surrounding tissue. Three carotids were occludes, one of them reconstructed with vascular prosthesis, two were resected. There were no perioperative hemiplegias or deaths. Before operation, one case had atrophy of left side of tongue and fixed left vocal card; two cases had Horner syndrome. After operation, eight cases had 13 cranial nerve deficits, they were: two cerchnus, four glossal deviation, three Horner syndrome and one drop of oral corner, one choking cough. Pathologic diagnosis included nine malignant carotid body tumors, two with capsule, seven without capsule, one cervical and one lung metastasis. Two of them underwent radiotherapy. The median follow-up was 6 years (range: 6 months-14 years). Six patients survived. Two cases died, one died of cervical recurrence, the other of lung cancer. One case was lost.</p><p><b>CONCLUSIONS</b>Malignant carotid body tumor is rare in clinic, and often invade the carotid and cranial nerve, the diagnosis of malignant tumor should base on occurring extensive invasion of adjacent organs and metastasis; Wide surgical excision should be selected early, radiotherapy is effective, the effect of chemotherapy is uncertainty.</p>