A 29-year-old man presented with lethargy, headache, high fever, and visual disturbance. Neurological examination showed mydriatic pupil, ptosis, diminished light reflex, and ophthalmoplegia on the left. Magnetic resonance (MR) imaging showed the typical findings of pituitary apoplexy, and cerebral angiography disclosed mild narrowing of the A1 segment of the left anterior cerebral artery (ACA). Transsphenoidal tumor resection was performed. Transient severe right hemiparesis occurred directly after the operation. Computed tomography demonstrated cerebral infarction in the territory of the left Heubner's and medial lenticulostriate arteries. Pituitary apoplexy followed by cerebral infarction is very rare. Vasospasm of the perforating arteries of the ACA probably caused the cerebral infarction. Subarachnoid blood or vasoactive agents released from the tumor were the most likely cause of the vasospasm. MR imaging findings of contrast enhancement around the vessels may indicate reactive processes around the vessels.