We have analyzed the results of a multicenter study on peripheral blood stem cell transplantation (PBSCT) performed on 55 patients suffering from various neoplastic diseases. After myeloablative therapy, they received a median of 6.8 x 10(8)/kg MNC and 11.4 x 10(4)/kg CFU-GM harvested by a median of 9 apheresis after mobilization with chemotherapy alone. As of date, 34 of the 55 patients are alive and 28 of them are in continuous complete remission after a follow-up of 30 months. The probability of survival was related to the disease status at transplant, CR/PR vs. PD (p = 0.0001) and the bone marrow involvement, BM-vs. BM+ (P = 0.009). Furthermore, a comparative study on speed of engraftment and clinical management was conducted on the 55 PBSCT patients as well as on 41 autoBMT and 52 alloBMT patients. Days to reach WBC > 1.0 x 10(9)/L, PMN > 0.5 x 10(9)/L and PLT > 50 x 10(9)/L was 12/14/33 for PBSCT, 17/20/23 for ABMT and 15/16.5/18 for BMT, respectively. Days with fever > 38 degrees C, systemic antibiotic therapy and length of hospitalization was 3/12/36 for PBSCT, 5/18.5/42 for ABMT and 9/25/46 for BMT respectively.