We present the case of a 59-year-old Midwestern farmer who presented with altered mental status, dysarthria, urinary incontinence, and a right-sided L5 dermatomal rash; he had recently received a course of oral corticosteroids for treatment of radicular low back pain. Lumbar puncture revealed the presence of varicella zoster virus (VZV) and IgM antibodies against a California-group encephalitis virus, later confirmed as Jamestown Canyon virus (JCV). Unfortunately, the patient's health declined despite aggressive treatment, developing progressive subarachnoid hemorrhage. He died after withdrawal of supportive care following 3 weeks in the intensive care unit. To our knowledge, this is the first documented case of encephalitis associated with coinfection by VZV and JCV. While the relative contributions of these viral pathogens to the patient's illness are difficult to ascertain, the clinical features of this case are consistent with co-pathogenesis, possibly driven by antecedent corticosteroid use. This case highlights the emerging role of viral coinfections in the etiology of viral illnesses.