BACKGROUND: The pituitary adenoma causing acromegaly is typically resected through a transsphenoidal approach and visualized with an operating microscope or endoscope. We undertook a systematic review and meta-analysis examining the clinical efficacy of endoscopic and microsurgical approaches. METHODS: Relevant studies using either endoscopic or microscopic transsphenoidal approaches for growth hormone pituitary adenomas were identified until February 2016. Data were extracted and analyzed according to predefined clinical end points. RESULTS: We identified 31 studies, in which 950 patients underwent endoscopic transsphenoidal resection and 2137 patients underwent microsurgical transsphenoidal resection. Patients undergoing microsurgery were less likely to present with hypothyroidism (10.7% vs. 19.1%, P = 0.033, 462 vs. 156 patients) and less likely to have macroadenomas (66.9% vs. 83.8%, P <= 0.001, 1484 vs. 884 patients); adenomas with cavernous sinus invasion (21.3% vs. 44.4%, P = 0.036, 592 vs. 558 patients); and a lower mean tumor volume (17.84 vs. 20.54 mm(3), P = 0.012, 158 vs. 248 patients). Patients treated via the endoscopic approach were more likely to achieve remission for noninvasive macroadenomas (83.8% vs. 66.9%, P <= 0.001, 115 vs. 365 patients). Sinusitis (15.6% vs. 2.6%, P < 0.001, 241 vs. 295 patients) and intraoperative cerebrospinal fluid leak (21.6% vs. 1.0%, P = 0.022, 697 vs. 127 patients) were more common in patients treated endoscopically, and meningitis (0.7% vs. 1.7%, P = 0.027, 511 vs. 1513 patients) was more common in patients undergoing a microsurgical approach. CONCLUSIONS: Our study shows the clinical utility of the endoscopic approach and demonstrates potential benefits including increased remission rates with noninvasive macroadenomas and a lower rate of meningitis.