We retrospectively reviewed the clinical course of 66 patients treated for generalized tonic-clonic status epilepticus at the Ege University neurological intensive care unit from 1988 to 1997. Seventy-two per cent of the study group had a pre-existing seizure disorder, and antiepileptic drug withdrawal was the most prominent cause of status epilepticus. The other causes included drug toxicity, central nervous system infection, cerebrovascular disease, tumour and trauma. Seventy-three per cent of all patients responded to the first-line therapy (diazepam and/or phenytoin), and the remainder were considered to have refractory status epilepticus and required pentobarbital anaesthesia. Overall case fatality was 21%, but death could be attributed directly to status epilepticus and/or treatment complication in 10% of the study group. Major determinants of fatal outcomes were: increasing age, longer duration of status epilepticus before initiation of therapy and central nervous system infection as a causal factor.