Twenty patients, 16 male and 4 female (aged 11-76 years), with metastatic pheochromocytoma were treated in our Institution between 1985 and 1990. Metastases occurred in all patients: at presentation in 11 patients, with a 10 to 30 month delay in 7 patients, and 9 and 28 years later respectively in 2 patients. Catecholamines hyperproduction was present in all patients. Metaiodobenzylguanidine (MIBG) uptake was found in 16 patients after a diagnostic dose and only after a therapeutic dose in 1 patient. Surgery was performed on primary tumor (18 patients) and on distant metastases (10 patients). 131I-MIBG therapy was performed in 11 patients, 9 of whom were evaluable. The cumulative activity ranged from 3.7 to 26.3 GBq (100 to 711 mCi) in 1 to 6 courses. We observed symptomatic improvement (5 patients) and partial tumor response in 2 patients, which lasted for 28 and 9 months respectively, terminating with a rapidly progressing disease involving the bone marrow. Stabilisation was observed in 3 patients. Moderate myelosuppression occurred in 4 patients. Fifteen patients died with a median survival of 16 months (range 3-60). Response to therapy was poor and further evaluation of the presently available therapeutic approaches is needed.