From 1972 to 1980, 210 patients underwent transsphenoidal operation for removal of a prolactin-secreting tumor. Eight of the patients had primary amenorrhea. All eight patients had had a normal thelarche and pubarche without menarche, and all eight had hyperprolactinemia and abnormal findings on sella turcica tomography. After operation, only one patient did not have persistent hyperprolactinemia, and this patient was the only one who began spontaneous menses. The data indicate that although prolactin hypersecretion interferes with menstrual function, it does not alter other pubertal development and that, if the source of the excessive prolactin can be removed, the removal alone may initiate spontaneous menses. In this report, however, patients with prolactin-secreting adenomas and primary amenorrhea had a high incidence of persistent hyperprolactinemia after operation (seven of eight patients).