Acromegaly is caused by excessive secretion of growth hormone (GH) and presents with a variety of clinical manifestations, including facial disfigurement and abnormally large hands and feet, as well as diabetes mellitus, hypertension, and sleep-disordered breathing (SDB). Although SDB is known to be associated with serious symptoms, there have been few study reports, and no clear consensus has been reached regarding the method of assessment of individual treatments. We report herein on the results of surgical intervention with transsphenoidal surgery (TSS) for acromegaly and assessment of the treatment effect after the intervention. We studied 6 patients who received a diagnosis of acromegaly complicated with SDB and underwent TSS at our hospital. Polysomnography (PSG) was performed before and after TSS, and the polysomnograms were analyzed. We also examined changes in the levels of GH and insulin-like growth factor-1 (IGF-1) on blood biochemistry. In 6 cases of acromegaly with SDB, we were able to confirm endocrinologic improvement of TSS with blood biochemistry. However there was no meaningful improvement in the PSG index for SDB.