Focal neurological deficits (FNDs) in patients with arteriovenous malformations (AVMs) have been widely attributed to the phenomenon of “cerebral steal.” The incidence of focal deficits was investigated in a large prospective sample. Methods Using data from patient history and examination, CT or MRI, and transcranial Doppler sonography, we studied 152 consecutive, prospective AVM patients for evidence of FNDs unrelated to a hemorrhagic event. Feeding mean arterial pressure was measured during superselective angiography. Results Two (1.3%) of 152 patients met the criteria for a progressive FND. Nonprogressive FNDs were seen in 11 (7.2%) patients (stable in 4.6%, reversible in 2.6%). The median observation time period was 17 months (range, 1 to 60 months). There were no differences in transcranial Doppler mean velocities in feeding arteries in FND versus non-FND groups (118 plus minus 44 versus 112 plus minus 37 cm/s, P more than.05) or pulsatility indexes (0.53 plus minus 0.20 versus 0.55 plus minus 0.15, P more than.05). Feeding artery pressure was similar in FND (n equals 10) and non-FND (n equals 96) groups (39 plus minus 16 versus 39 plus minus 16 mm Hg at a systemic pressure of 82 plus minus 18 versus 75 plus minus 14 mm Hg, NS). Conclusions Nonhemorrhagic focal neurological syndromes in AVM patients are infrequent. Progressive deficits are especially rare. There was no relation between feeding artery pressure or flow velocities and FND. There does not appear to be sufficient evidence to assign steal as an operative pathophysiological mechanism in the vast majority of AVM patients. © 1995 American Heart Association, Inc.