Three patients had status epilepticus appearing de novo as the presenting manifestation of Epstein-Barr virus (EBV) encephalopathy. Clinical findings of infectious mononucleosis were absent and EBV-specific serologic tests made or confirmed the diagnosis in each case. Epstein-Barr virus should be considered as a potential cause when status epilepticus occurs in the absence of previous seizures or an identified cause of seizures. The diagnosis may be made in some cases only with the use of EBV-specific serologic testing.