Non-convulsive status epilepticus (NCSE) is an under-recognised but treatable condition with considerable associated morbidity. The files of adult admissions were reviewed over four years, during which time 50 episodes of NCSE were diagnosed in 45 patients. These findings suggest a broad age range with various states of mental acuity and an association with both learning disabilities and acute systemic infection. Approximately half of the patients had a previous diagnosis of epilepsy at the time of admission, and half had a history of generalised tonic-clonic seizures immediately before the onset of their illness.