The pathophysiology of functional adenomas of the anterior pituitary gland can be understood in the context of the central neural control of anterior pituitary secretion and by the fact that the cell types of the anterior pituitary gland generally express a single polypeptide hormone. Functional pituitary adenomas arise de novo from one or more of these cell types, but a defect in hypothalamic regulation can contribute to tumorigenesis and sometimes result in persistent tumor recurrence despite local surgical cure. The recent advances in molecular biology, radioimmunoassay, neuroradiology, and transsphenoidal microneurosurgery techniques have greatly improved our understanding of the pathophysiology of these tumors, enhanced diagnostic accuracy, and led to newer medical and surgical therapeutic approaches. This conference reviews the molecular and cellular pathophysiology, causes, diagnosis, clinical features, and medical and surgical management of the two common functional pituitary adenomas, prolactinoma and somatotropinoma.