Immunosuppressive therapy is a double-edged sword and causes a risk for some complications, such as opportunistic infections and posttransplant lymphoproliferative disease. The most likely risk factors for posttransplant lymphoproliferative disease are Epstein-Barr virus serology mismatch, prolonged and high viral load for Epstein-Barr virus, higher doses of immunosuppressive therapy, and cytomegalovirus infection. Transplant recipients who are seropositive for Epstein-Barr virus show a lower risk for posttransplant lymphoproliferative disease than seronegative recipients. Here, we present a 3.5-year-old boy who was seropositive for Epstein-Barr virus and developed posttransplant lymphoproliferative disease 18 months after liver transplant with a previous history of cytomegalovirusrelated pneumatosis intestinalis.