We report the case of a 61-year-old male presenting with a giant nonfunctioning pituitary tumour extending into the third ventricle and thereby causing obstructive hydrocephalus. The main complaints consisted of disturbed vision and somnolence. The patient was initially treated by ventriculoperitoneal shunting, with immediate improvement of his mental status. Transcranial resection of the tumour was performed shortly thereafter, but only a limited part of the tumour could safely be removed. By immunohistochemistry the diagnosis of gonadotroph adenoma was made. After the operation, the patient's vision deteriorated temporarily. Because of the risk of further damage to the optic nerve, radiation therapy was postponed. Instead, treatment with the long-acting dopamine agonist cabergoline was instituted, which resulted in a gradual improvement of vision. Two years later a transsphenoidal operation was performed because of acute worsening of the visual fields due to central tumour necrosis with slight volume expansion. Vision improved considerably after surgery. Radiotherapy is scheduled in the near future. This case is an illustration of the complications of giant nonfunctioning pituitary adenomas. The therapeutical approach to obstructive hydrocephalus in these instances is reviewed.