Transsphenoidal surgery (TSS) is a well recognised treatment for secreting pituitary adenomas, however a very wide variation of clinical outcomes and recurrence rates has been reported, depending on the different criteria used to define the cure. We reported the clinical outcome of a large series of patients operated on for a secreting pituitary adenoma according to the most recent stringent criteria of biochemical remission nowadays accepted. One hundred and twenty-five consecutive patients with a secreting pituitary adenoma (42 PRL-, 67 GH- and 16 ACTH-secreting adenomas) who were operated on by the two same neurosurgeons were considered for the study. Biochemical remission of disease was achieved in 56% of patients; 78% for patients with microadenoma and 47% for patients with macroadenomas, respectively. No cases of mortality or major immediate postoperative complications were observed. Tumour size, high hormone levels and dural invasion were significantly correlated to a poor surgical outcome. The recurrence rates ranged between 0 and 24%, being higher for PRL-secreting tumours. In conclusion, TSS is safe and effective in secreting pituitary tumours. It is still the first treatment for GH- and ACTH-secreting adenomas, whereas in patients with prolactinomas, surgery should be reserved for cases of resistance or intolerance to dopamine agonists.