Twenty patients in whom the diagnosis of an intracranial arteriovenous malformation was suspected either by the history and clinical findings or by abnormal periorbital Doppler flow are discussed. Sixteen patients had only minor complaints or inconclusive signs or were clinically asymptomatic; 4 others presented with the syndrome of a carotid cavernous fistula. Patients were further examined by means of transcranial Doppler sonography, computed tomographic scanning, and cerebral angiography. In 17 patients, the diagnosis of an arteriovenous malformation could be established by transcranial Doppler sonography and could be confirmed by angiography. Transcranial Doppler sonography gave false negative results in 1 and false positive results in 2 patients. Our findings demonstrate the usefulness of modern ultrasound techniques in the assessment of small or even occult intracranial arteriovenous shunts before subjecting patients to more invasive procedures.