9 patients (8 males 1 female, middle age 24.3 years, range 20-41) affected by primary mediastinal germ cell tumor were surgically treated in our department. They were 4 seminomas, 2 embryonal carcinomas, 1 malignant teratoma and 2 benign teratomas. Three patients were asymptomatic; cough, dyspnea and chest pain were the most frequently observed symptoms. The staging work-up did not show signs of metastatic disease in the malignant types. Benign teratomas underwent complete excision. In one patient suffering from seminoma radiotherapy and chemotherapy caused complete remission of the disease. In the others cases remission of the neoplasm was obtained by resection and adjuvant therapy in 3 cases, by neoadjuvant treatment and excision of the residual mass in 3 cases. Among the patients suffering from seminoma, 2 are dead at 60 months since initial treatment and 2 are alive at 132 and 120 months respectively. Among the patients with malignant nonseminomatous tumours, 2 are alive at 60 and 36 months and 1 patient is dead at 13 months. Two patients with benign teratoma are alive at 189 and 168 months respectively. At present a multimodality treatment including surgery, radiotherapy and cisplatin-based combination chemotherapy, give the most satisfactory results in the treatment of malignant mediastinal germ cell tumours.