Giant intracranial aneurysms (GIA) are rare and manifest primarily through subarachnoid hemorrhage (SAH), cerebral ischemia, or progressive symptoms of mass effect. Transcranial Doppler (TCD) can be used to monitor cerebral vasospasm after treatment of intracranial aneurysm allowing the adjustment of therapeutics and avoiding complications. The authors present a clinical case of a patient with a ruptured intracranial giant aneurysm in which TCD was essential to monitor vasospasm and intracranial hypertension (IH). A 53-year-old male was admitted due to a sudden headache and impaired consciousness, left hemiparesis, and dysarthria. Cerebral CT scan and CT angiography at admission showed a giant aneurysm of the right middle cerebral artery (MCA) with extensive and diffuse intraventricular SAH of Fisher grade IV and Hunt and Hess grade 4. Clipping, placement of an intracranial pressure sensor, and external ventricular drain (EVD) were performed on the same day, with difficulty in preserving the M2 branch and complicated by postoperative extensive right MCA ischemia. On day three of hospitalization, TCD revealed an increased pulsatility index (>1.5) with clinical deterioration leading to re-intervention for a decompressive craniectomy. On day six, a TCD follow-up was performed to monitor blood flow complications, and particularly vasospasm, showing a severe increase in middle blood flow velocity (MBFV) in the right MCA of 205 cm/s and Lindegaard Index > 6. Daily surveillance by TCD was maintained to guide clinical management since the attempt to withdraw the EVD led to clinical deterioration with subsequent worsening of vasospasm. Improvement occurred after surgery as ventriculoperitoneal shunt insertion was performed. TCD had a major role in the clinical orientation of SAH as well as in intracranial pressure management and was decisive to establish long-term treatment.