Pituitary adenomas comprise approximately 10% to 20% of all central nervous system neoplasms whereas autopsy series have suggested that the incidence of pituitary adenoma in the general population may approach 25%. Several treatment modalities are used in the treatment of pituitary adenomas, including observation, surgery, medical intervention, and radiotherapy. The treatment modality employed depends greatly on the type of pituitary adenoma and presenting symptoms. This review will discuss the biology of pituitary adenomas and the current management principles for the treatment of prolactinomas, Cushing disease, acromegaly, and nonsecretory adenomas, with an emphasis on the published radiotherapeutic literature.