We present the results from the evaluations of three children ages of 2, 7, and 11 years with hemiparesis and multiple white-matter lesions on magnetic resonance images (MRIs). The initial symptoms were mainly acute/subacute hemiparesis in all and headache/vomiting in one of them. Before admission, one of them had a history of upper respiratory tract infection, whereas another had undergone urinary tract surgery, and the other reported no history of any infection or stress-related factor. In all of the children, MRI showed multiple superficial and deep white-matter hyperintensity in T2-weighted and proton density images with perifocal edema in the acute phase. During the symptomatic period, all of the patients underwent corticosteroid treatment. Whereas two of the patients demonstrated signs of recovery during the first week of treatment, the other patient demonstrated almost a full recovery with minimal neurologic sequela. Follow-up MRI demonstrated not only a remarkable decrease in the size and number of the lesions, with complete resolution for many of them, it also demonstrated a loss of contrast enhancement. None of these three patients, who had been followed up clinically and through MRI for 5 years, have shown either a clinical relapse or new lesions. The clinical pictures and MRI of the children were different in some aspects from acute multiple sclerosis and acute disseminated encephalomyelitis. Regarding both the clinical follow-up and treatment strategy, it is essential and interesting to state the fact that tumefactive lesions involving both hemispheres are likely to appear during the monitoring of the monophasic courses among inflammatory demyelinating diseases of childhood such as acute disseminated encephalomyelitis.