Background: Analysis of infraslow EEG activity (ISA) has shown potential in the evaluation of patients with epilepsy and in differentiating between focal and generalized epilepsies. The purpose of this report is to present a girl with Sturge-Weber Syndrome (SWS) who was identified to have infraslow status epilepticus (ISSE), which successfully resolved after Midazolam administration Methods: The continuous EEG recording of a 5-yr-old girl with known Structural Epilepsy due to Sturge-Weber is presented. The patient presented to the ED with acute confusion, eye deviation and right hemiparesis similar to two previous admissions. ltm-eeg showed diffuse slowing. DWI obtained within 72-hr showed no ischemic changes, analysis of the EEG nfraslow (ISA) activity was undertaken using LFF 0.01 AND HFF of 0.1 Hz respectively. Results: Continuous subclinical unilateral rhythmic ictal ISA was identified. This was only evident in the left hemisphere which correlated with the structural changes due to SWS. A trial of continuous IV midazolam resulted in immediate resolution of the contralateral hemiparesis and encephalopathy. Conclusion: Continuous prolonged rhythmic ictal Infraslow activity (ISA) can cause super-refractory subclinical focal status epilepticus. This has not previously reported, and we propose this should be called Infraslow status epilepticus (ISSE). ISA analysis should be performed in all patients with unexplained subclinical status epilepticus.