Although usually asymptomatic, a persistent trigeminal artery (PTA) can rarely be associated with a direct fistula to the cavernous sinus (ie, trigemino-cavernous fistula). We present three patients with trigemino-cavernous fistulas; two were subsequently treated using modern endovascular techniques while the third initially declined therapy. We then review the literature of reported cases of this unusual entity. The aberrant anatomy associated with a PTA presents unique challenges to the management of these lesions, and must be well delineated prior to treatment. Finally, conservative management of trigemino-cavernous fistulas, either de novo or recurrent, may be considered if they demonstrate no evidence of cortical venous reflux and patient symptoms are tolerable.