Cerebral vasospasm is an uncommon complication following transsphenoidal surgery (TSS) of a pituitary adenoma. Therefore, neither its physiopathology nor its management are clear. We present a case of vasospasm after TSS and we discuss about its etiology and treatment. A 52-year-old woman presented with hirsutism, without neurologic symptoms. A MRI showed a pituitary macroadenoma. The patient underwent an endoscopic transsphenoidal approach. Post-operative CT scan revealed an extensive subarachnoid haemorrhage (SAH). On postoperative 7th day, she developed an abrupt mixed aphasia. An urgent arteriography showed left middle cerebral artery vasospasm, so intra-arterial nimodipine was administered. After that, vasospasm disappeared and the patient recovered completely. The key to successful management of this rare complication is a high index of suspicion. The presence of postoperative SAH seems to definitely contribute to its apparition. Therefore, treatment in concordance with protocols for vasospasm due to aneurysmal SAH is recommended.