A 52-year-old Japanese woman suffering from AML (FAB classification M4) in her first remission received an autologous peripheral blood stem cell transplant (APBSCT). She was seropositive for CMV prior to APBSCT. Her post-APBSCT course was complicated with CMV-associated disease and hemophagocytic syndrome. Finally, CMV interstitial pneumonia developed and death ensued. Even after APBSCT, there can be a short period of immune deficiency resembling that occurring following allogeneic or autologous BMT. CMV infection must be considered in the differential diagnosis in cases of unexplained fever or pneumonia following APBSCT.