Pituitary adenomas are relatively common neoplasms representing 10% to 15% of all intracranial tumors [1]. The prevalence of pituitary adenomas in autopsy series [2] and MRI studies [3] is similar to10% to 20%; however, many of these tumors never produce a clinically recognizable disease. Nevertheless, about 2 to 8 in 100,000 individuals per year will seek medical evaluation because of abnormal hormonal secretion or mass effects related to tumors of the sella turcica [4,5]. The vast majority of these will be benign pituitary adenomas, with only 9% to 10% from other causes. An understanding of the types of tumors affecting the pituitary and sellar region, their presentation, and the appropriate biochemical and radiologic evaluation is crucial to accurate diagnosis. Furthermore, while treatment generally requires the involvement of specialists in endocrinology, neurosurgery, and radiation oncology, it is important that the primary care physician understand the indications, goals, and risks of available treatment options. This article will focus on the diagnosis and treatment of two of the more common pituitary adenomas: prolactinomas and growth hormone-secreting tumors. Nonsecreting or gonadotroph adenomas and thyrotroph adenomas will also be briefly discussed. Recent changes in management guidelines and some promising new medical therapies will be reviewed. Adrenocortocotroph tumors producing Cushing's disease will be discussed in a separate article.