Fourty acromegalic patients were evaluated and treated at the Neurosurgical Division (University of Buenos Aires). They were clinically studied, with basal and dynamic GH (Growth Hormone) measurements, exhaustive endocrinological assessment and neuroimaging investigation. These studies were performed before and after treatment at annual intervals. According to the radiological and surgical findings, patients were categorized into four grades: g. I (microadenomas), g. II (intrasellar macroadenomas), g. III (expansive adenomas) and g. IV (invasive adenomas). All the patients were operated on by the transsphenoidal approach (two were also subjected craniotomy) and received postoperative radiotherapy at a 4,500 rads dose. The patients were followed-up from 2 to 11 years (mean 4.8 years). Thirty-two cases (80 %) were considered as cured (without clinical signs of evolution, GH measurements less than 5 ng/ml and without radiological evidence of tumoral recurrence): 7 out of these (17.5 %) failed to normalize GH dynamic testing. Eight patients (20 %) persisted with active acromegaly. In g. I cases, 100 % were cured (7 patients). In g. II (83.3 %) (15 patients). In g. III 72.7 % (8 cases). n g. IV, 2 patients were cured and 2 were not. There were not deaths related to treatment. The results of the present series show that transsphenoidal microsurgical resection followed by radiotherapy is an effective therapeutic modality for reaching control of the disease. The authors conclude that the best results are achieved in enclosed adenomata, while invasive tumors are hardly amenable to cure. Finally it must be pointed out that a significant number of patients still have abnormal dynamic GH testing in spite of the lack of evidence of adenoma recurrence: it will be required further research on this phenomenon as some authors consider it as a biochemical manifestation of tumoral cell persistance and others, as the present series' authors, as a merely functional disorder.