An uremic patient, in chronic dialytic treatment, developed a Miller-Fisher's syndrome acutely after a dialysis. Clinical diagnosis was supported by findings of persistent conduction block in upper and lower extremities and by raised proteins in CSF. Contrast-enhanced CT and MRI scans excluded lesions in the brain stem. The course of this illness was characterized by waxing and waning in cranial nerve deficits, in relation with the hemodialytic treatments. We suggest that, when the patient recovered, reversible changes occurred in the nerves, either due to reversibly impaired sodium permeability or to an ischemic process related to the ultrafiltration dialysis.