A total of 349 patients with pituitary tumors, including acromegaly, Cushing disease, Nelson syndrome, prolactin-secreting adenoma, and chromophobe adenoma, have been treated with heavy-particle radiation during the past 17 years. The incidence of side effects has been low. Only 30 patients, 8.6%, have died, most of preexisting cardiovascular complications. Heavy particle therapy provides a form of treatment with no mortality and extremely low morbidity, and its use in treating pituitary disorders has resulted in dramatic improvement in the signs and symptoms of patients with acromegaly and Cushing disease.