Clinical, computed tomographic (CT), and magnetic resonance imaging (MRI) correlations of subacute sclerosing panencephalitis with an atypical onset are presented in three children. In all three patients, the disease began similarly, with unilateral neurologic deficit followed by gnosis, praxis, and memory dysfunction corresponding to massive one-sided lesions. The first patient demonstrated right frontal-lobe syndrome and polymorphic extrapyramidal hyperkinesias; MRI showed a large high-signal lesion in the right frontal lobe, while CT was normal. The second patient displayed a disease onset with left-sided hemiparkinsonism and involuntary movements correlating to the MRI finding, ie, a massive rightsided occipitotemporoparietal subcortical lesion. An acute, stroke-like episode represented the first symptom in the third child. CT visualized cerebral, mainly left-sided cortical atrophy. In all three children, CT and MRI revealed significantly progressing brain atrophy at the disease's latest stages. We discuss the role of MRI in detecting early pathologic changes in children with subacute sclerosing panencephalitis.