I have described some of the currently known characteristics of a group of pituitary adenomas that produce no syndrome of hormone secretion. These tumors, termed endocrine-inactive, are engaged in low levels of endocrine activity and under certain circumstances can secrete hormones, primarily glycoprotein hormones and their subunits. I have advocated a more vigorous attempt to achieve total removal of these usually large tumors because of my conviction that many, although certainly not all, can be removed completely with preservation of anterior pituitary function and, possibly, recovery of lost anterior pituitary function. Transsphenoidal removal of endocrine-inactive tumors is safe as well as effective and, in the foreseeable future, will continue to be the treatment of first choice.