From 1972 to 2002, we diagnosed and treated 22 cases of subacute sclerosing panencephalitis. We report on two pediatric patients with fulminant subacute sclerosing panencephalitis who had atypical clinical manifestations. In both patients diagnosis was confirmed by elevated titers of CSF and serum antimeasles antibodies. Patient 1 presented with behavioral disorder, dysarthria, and drop attacks, while Patient 2 presented with partial complex seizures. Mental difficulties, personality changes, or myoclonus were not noticed in Patient 2. In both our patients stage I was not prominent, and stage II was of shortened duration. In spite of treatment with isoprinosine and interferon-alpha, both our patients deteriorated rapidly and died 2.5 and 4 months, respectively, after the onset of neurologic symptoms. Both atypical presentation and rapid clinical course observed in our patients could cause problems in making final diagnosis of subacute sclerosing panencephalitis. Therefore, subacute sclerosing panencephalitis should be included in differential diagnosis of acute unexplained encephalopathic diseases.