We report a patient whose cryoglobulinemic vasculitis recurred due to reactivation of lamivudine-resistant HBV. Our patient with hepatitis B-related cryoglobulinemic vasculitis was administered lamivudine. Her vasculitis regressed, ALT normalized, HBV-DNA became negative. Under lamivudine therapy, her cryoglobulinemic cutaneous vasculitis recurred. ALT increased significantly; it was found that tyrosine-methionine-aspartate-aspartate (YMDD) motif in the DNA polymerase gene had been replaced by YIDD. Adefovir was added to lamivudine. During follow-up, her purpura disappeared, ALT normalized, HBV-DNA became negative. Our patient is the first whose cryoglobulinemic vasculitis recurred under lamivudine, who had a HBV virologic breakthrough with YMDD mutation, and was successfully treated with adefovir.