Salvage human leukocyte antigen-haploidentical hematopoietic cell transplant using posttransplant cyclophosphamide has shown promising results for graft failure in various hematological disorders. However, to our knowledge, no such findings have been reported for a case of chronic active Epstein-Barr virus infection, although graft failure is relatively common in patients with chronic active Epstein-Barr virus infection. We report a case of a 32-year-old woman with natural killer-cell type chronic active Epstein-Barr virus infection who experienced graft failure after a first allogeneic hematopoietic cell transplant from an unrelated human leukocyte antigen-matched donor.The patientreceived a second allogeneic hematopoietic cell transplant with human leukocyte antigen-haploidentical hematopoietic cell transplant using posttransplant cyclophosphamide (cyclophosphamide, 50 mg/kg, on day 3 and day 4) following reduced-intensity conditioning as rescue therapy. Neutrophils successfully engrafted on day 19, and the patient sustained remission without severe transplant-related complication 10 months after salvage human leukocyte antigen- haploidentical hematopoietic cell transplant using posttransplant cyclophosphamide. This report suggests that salvage human leukocyte antigen- haploidentical hematopoietic cell transplant using posttransplant cyclophosphamide may be a feasible therapeutic option for graft failure in patients with chronic active Epstein-Barr virus infection.