Coexistence of pituitary adenoma, intracranial meningioma and cerebral aneurysm has never been described. We report on a patient with GH-secreting pituitary macroadenoma associated with a right frontal meningioma and with two intracavernous asymptomatic aneurisms. A 61-year-old woman was referred to our Endocrine Unit 13 years after a right frontal craniotomy for a pituitary tumour. Endocrine investigation showed high levels of IGF-1 (560 ng/ml) and increased basal serum GH (56 ng/ml) levels, not suppressed after OGTT. MRI showed persistence of a homogeneously enhancing intra- and suprasellar lesion, compressing the visual pathways, with bilateral intracavernous invasion and simultaneous coexistence of a right intracavernous internal carotid artery (ICA) aneurysm in direct contact with the pituitary tumour. Somatostatin analog treatment normalized GH and IGF-1 levels. Eight months later, the patient underwent a balloon ICA occlusion with disappearance of the right ICA aneurysm. One year later, a new MRI confirmed the presence of the pituitary mass showing also a right intracranial frontal meningioma and a new ICA aneurysm on the left side. Previous studies have suggested that prolonged GH hypersecretion could play a role in the genesis of intracranial aneurysms, inducing atherosclerotic and/or degenerative modification of the arterial walls. Other aetiological factors include a mechanical effect due to a direct contact between adenoma and aneurysm. Coexistence of pituitary adenoma and intracranial meningioma is a rare event, but also for this association it has been suggested that GH or other growth factors could play a role in appearance or in growth of meningioma. In our case, meningioma appeared and grew, despite the effective treatment of acromegaly.