Medical therapy with dopaminergic drugs is the preferred initial treatment for symptomatic prolactin (PRL)-secreting adenomas; but in recent years, there has been a renewed interest in surgery. The aim of this study is to report a large series of patients operated for prolactinoma in the last 10 yr. A total of 120 consecutive patients (93 female, 27 male) underwent surgery from January 1990 to December 1999. Their mean age at surgery was 29.7 +/- 0.9 yr. Fifty-nine patients (49.2%) had a microadenoma, and the remaining 61 (50.8%) had a macroadenoma, of which 24 (20%) were intrasellar and 37 (30.8%) were extrasellar adenoma. Magnetic resonance imaging signs of invasion of the cavernous sinus were detected in 18 patients (15.0%). Thirty-one patients (25.8%) had never been treated before, whereas the remaining 89 (74.2%) had received dopaminergic drugs. After surgery, normalization of PRL levels occurred in 77 patients (64.2%). Logistic regression analysis showed that the only predictive factor of unsuccessful surgery was a high preoperative PRL level. Recurrence of hyperprolactinemia occurred in 13 of the 77 cured patients (16.9%) during a mean follow-up of 50.2 +/- 3.0 months; the 5-yr disease-free survival was 75.9%. Extrasellar extension of the tumor and presence of a postoperative PRL response to TRH were associated with a lower risk of relapse. In summary, surgery normalized PRL levels and relieved symptoms of hyperprolactinemia in most patients. Recurrence of hyperprolactinemia occurred within 4 yr after surgery. Transsphenoidal surgery can be offered as a definitive therapy, especially to patients with intrasellar tumors.