Sleep apnoea syndrome (SAS) is common in acromegalic patients. Occasionally, the relief of apnoeas after treatment of the acromegaly has been documented. We report the cases of three patients with acromegaly and severe obstructive sleep apnoea, who demonstrated a manifest improvement (respiratory disturbance index (RDI) <20) after treatment with octreotide, indicating that this drug may be effective in this disturbance. In one case, SAS disappeared although the growth hormone level was not fully normalized. This raises the intriguing hypothesis that octreotide has an effect on respiratory control or on the upper airway, that is not directly related to its action on production of growth hormone.