From our series of 203 patients with cerebral vascular lesions, 18 (9%) could be included in the multiple arteriovenous malformation category. There were five patients with Rendu-Osler-Weber, one with Wyburn-Mason syndromes and two with concurrent arteriovenous malformations. The remaining ten patients (4%) had multiple brain arteriovenous malformations. Careful angiography with magnification is necessary to try to diagnose multiple brain AVMs, since these sometimes become apparent only after embolization of a larger dominant AVM. The incidence of multiple brain arteriovenous malformations is likely to have been underestimated due to the failure to recognize micro-arteriovenous malformations associated with larger arteriovenous malformations.