We describe three patients with acute encephalitis and motor-dominant polyneuropathy. All three patients were in their middle age and presented with features of encephalopathy with flu like illness. Cerebrospinal fluid (CSF) studies showed lymphocytic pleocytosis with increased protein. Brain magnetic resonance imagings (MRIs) showed symmetric high signal intensities in bilateral mesial temporal lobes and bilateral thalami in all patients. All three patients became quadriplegic and areflexic within two hospital days (HDs) and electrophysiologic studies revealed motor polyneuropathy. Viral or atypical bacterial infection was suspected, but no causative agent could be found. One patient expired on the twentieth hospital day, and the other two patients showed no or little improvement. To our knowledge, this combination of acute encephalitis with motor polyneuropathy has not been reported.