Brain edema with brain herniation during or after dialysis has been reported previously. However, coexisting lesions of the central nervous system (CNS) which might play a facilitating role were present in these case reports. Described here is an 18-year-old white man with renal failure who developed clinical signs consistent with brain herniation while receiving his first hemodialysis treatment. He died two days later, after discontinuation of the supportive therapy and after the confirmation of brain death. Autopsy results documented brain edema with uncal and cerebellar tonsillar herniation without other coexisting pathologic lesions. The etiology of brain edema during the initial phase of dialysis is discussed.