This is a rare case of Varicella zoster virus (VZV) lumbosacral plexopathy in an 84-year-old women presenting with lower limb weakness and rash. Contrast-enhanced MRI showed enhancement of the left L3-L5 descending nerves and left lumbosacral plexus consistent with inflammatory/infectious aetiology. Cerebrospinal fluid PCR confirmed VZV DNA and cerebrospinal fluid serological testing was positive for VZV immunoglobulin (Ig)M and IgG antibodies. The patient was treated with intravenous acyclovir but this was complicated by the development of acute renal failure attributed to acyclovir-induced nephropathy, requiring dose adjustment. After a prolonged course of oral acyclovir and inpatient rehabilitation, the patient made a partial neurological and functional recovery.