The authors present a serie of 40 histologically verified prolactin secreting adenomas. Thirty-four women and six men were explored using the usual techniques and operated by the transphenoidal approach with biological follow-up 3, 6 and 12 months post-operatively. Results were a function of tumor size and invasive potential. Although amelioration of the tumoral syndrome always resulted, fonctional and biological normalization were inconstant. Complementary anti-prolactin treatment (C.B. 154) was begun in the non-normalized patients, especially in the cases of invasive adenoma. --Normalization was achieved in 95% of enclosed adenomas, --In 61% of invasion adenomas. In those patients normalized following surgery a return to normal rythmic prolactin secretion was observed.