A patient with non-Hodgkin's lymphoma who received a CD34-selected autologous peripheral blood stem cell transplant (PBSCT) developed cytomegalovirus retinitis, adenovirus-associated haemorrhagic cystitis (HC) and fatal herpes simplex virus pneumonia. Depletion of mature T cells from the graft and a persistent decrease in CD4+ lymphocytes following PBSCT may have predisposed this patient to such viral infections. Infusion of cryopreserved autologous PBSC (containing mature T cells) was effective for adenovirus-associated HC. Immunosuppression and resultant viral infections may affect patients receiving CD34-selected autologous transplantation.