We searched the MEDLINE and PubMed databases for all articles published between January 1, 1990, and December 31, 2008, with the term status epilepticus combined with the terms outcome, mortality, morbidity, fatality, prognosis, coma, death,incidence, prevalence, and epidemiology. Only articles written in English or French were reviewed. Of 3043 articles initially identified, all but 529 were excluded on the basis of the title and abstract. The exclusion criteria included case reports, review articles, commentaries, treatment protocols, and studies with fewer than 30 patients. Articles specifically concerned with nonconvulsive SE were excluded, but articles in which data for convulsive SE (CSE) and nonconvulsive SE were given were considered. Inevitably, a distinction between CSE and nonconvulsive SE was not always made in some series, and these articles were included. Prospective and retrospective population- and hospital-based series were included. The search identified 7 population-based studies, with the remainder of the studies cited being hospital based. The reference lists of the identified articles were then examined for additional relevant studies. Common causes of SE were defined as causes listed in at least 1 of the population-based studies of SE that had an incidence greater than 1%. The major studies of CSE in the developing world are also reviewed to identify the predominant causes of CSE, although no attempt is made to analyze prognosis by cause, as is done for studies from the developed world.