The incidence of documented infections after autologous peripheral blood progenitor cells transplantation (PBPCT) was retrospectively evaluated in 86 consecutive patients (47 males 39 females; median age 36 years, range, 18-63) treated in our institution; 83 patients had refractory hematological malignancies (40 non-Hodgkin's lymphoma, 19 Hodgkin's disease, 17 multiple myeloma, 7 acute myeloblastic leukemia) and 3 had solid tumors (1 rabdomyosarcoma, 1 neuroblastoma, 1 osteosarcoma). All patients developed fever after transplantation lasting a median of 2 days (range 1-17); 20 instances of documented sepsis developed in 17 patients (19.7%). Gram positive microorganisms were implicated in all but 4 cases. There were no fatalities directly due to infections and no correlation was found between the risk of infection and reaching PMN > 0, 1 x 10(9)/L, PMN > 0.5 x 10(9)/L. In addition no specific risk factors related to age, disease, conditioning regimen, use of central venous catheter (CVC), type of transplant, and isolation measures were identified.