We describe 2 allogeneic stem cell transplantation patients who developed chronic graft-versus-host disease (GVHD) after dermatomal varicella-zoster virus (VZV) infection. Localized zoster did not respond to oral valaciclovir but did resolve with intravenous aciclovir. However, skin eruptions, eye/oral dryness, and liver dysfunction were observed at the healing stage of localized zoster, suggesting development of GVHD. Intensification of immunosuppressive therapy was required to control GVHD. Quantitative real-time PCR for VZV DNA was used to distinguish liver involvement by chronic GVHD from visceral dissemination of VZV in 1 patient. VZV infection may trigger chronic GVHD after allogeneic stem cell transplantation.