Pheochromocytoma is a catecholamine-producing tumor of the sympathetic nervous system which in 4-14% of the cases may be malignant. The differentiation between benign and malignant pheochromocytomas is very difficult, the presence of metastatic lesions and gross invasion into surrounding tissues are the lonely accettable parameters to confirm malignancy. Since the patients with malignant pheochromocytomas have a very poor survival rate, care must be taken for an early detections and a careful follow up. Three cases of malignant pheochromocytoma are reported. In one of these cases the tumor was a functioning mass; the other two cases presented by a hemorragic complication. A careful review of the pertinent literature allows to outline the correct approach to this rare pathology as for the diagnosis and the treatment, also including the actual criteria to establish its malignancy.