Thromboembolism after brain aneurysm embolization involves high morbidity/mortality and its conservative treatment is still a standard policy. We report the practical utility of transcranial colour-coded Doppler sonography (TCCS) in the early diagnosis and effectiveness of prompt intravascular intervention in the treatment of this condition. A 50-year-old woman developed acute neurological deficit after intravascular re-embolization of a brain aneurysm. Severely decreased blood flow velocity in the middle cerebral artery was revealed with TCCS and angiography confirmed nearly complete occlusion of the carotid artery. After heparin administration, intravascular thrombectomy was performed at the same session with implantation of a stent. The symptoms faded away within hours and the patient recovered fully. Prompt intravascular intervention could be a valuable and efficient alternative in the treatment of thromboembolism after embolization of cerebral aneurysm. TCCS enables early differential diagnosis of this potentially devastating sequel.