Epileptic encephalopathy (EE) with continuous spikes and waves during sleep (CSWS) (epilepsy with electric epileptic status during slow sleep phase or encephalopathy with electric epileptic status during slow sleep phase) is partially reversible age-dependent epileptic encephalopathy. It is characterized by a triad of symptoms: seizures, neurocognitive regression, and an electroencephalography pattern of electrical status epilepticus during sleep. This rare condition occurs in 0,5% of children and adolescents with epilepsy. Seizures usually start when the child is 2-4 years old. Several stages in CSWS are identified: dormant stage, prodromal stage, acute stage, and residual stage. EE epileptiform activity may be focal, multifocal, unilateral, asymmetric or symmetric bilateral, and diffusive. Treatment goals of CSWS include not only improved seizure control, but also a significant reduction in EEG epileptiform activity. Benzodiazepines and steroids are most effective.