We report on two children who presented acute, severe, neurological dysfunction with bilateral, reversible, selective thalamic lesions demonstrated by brain MRI. In both children neurological symptoms appeared two weeks after a febrile respiratory illness. Clinical conditions worsened in a few days to a stuporous state and tetraplegia in one and to coma with decerebrate posturing in the other. Three weeks after the onset, both children improved and recovered within one month. During the acute phase, brain MRI showed in both children bilateral hyperintense areas on T2-weighted sequences limited to both thalamic regions. During the follow-up, repeated brain MRI showed complete disappearance of abnormalities in one patient and a small residual left thalamic lesion in the other. In both patients hematological routine exams were normal. Bacterial and viral studies of serum and CSF were negative. CSF findings showed elevated white blood cell count and protein levels, with no oligoclonal IgG bands. Urine and CSF organic acids by GC/MS and plasma as well as CSF amino acids were normal. We believe that the benign evolution of this disorder and CSF findings strongly suggest a postinfectious process of the central nervous system.