Patients with refractory seizures, including those with Sturge-Weber syndrome, undergo functional studies in preparation for surgery Perfusion studies in Sturge-Weber syndrome by single photon emission computed tomography and positron emission tomography generally demonstrate hypoperfusion in the diseased tissue. We report perfusion-weighted magnetic resonance imaging results in 2 cases of Sturge-Weber syndrome with recent seizures. The affected cerebral tissue showed increased relative cerebral blood flow and volume with prolonged mean transit time and time to peak. Elevated relative cerebral blood flow could be attributed to seizures, whereas increased relative cerebral blood volume might have resulted from vasodilation due to seizure activity or chronic ischemia. These findings point to the variable results of functional studies in Sturge-Weber syndrome that might lead to miscalculations of the lesion area before surgery.