Pegfilgrastim (PEGFIL) has been found to be comparable to daily filgrastim (FIL) in managing chemotherapy-induced neutropenia. In the present study, we evaluated the ability of PEGFIL to mobilize stem cells in 38 consecutive patients with lymphoproliferative diseases (multiple myeloma, n = 18; lymphomas, n = 15; chronic lymphocytic leukemia, n = 5). Patients were mobilized using PEGFIL (6-18 mg as a single dose) during 2005-2006; 32 then received high-dose chemotherapy followed by autologous stem cell transplantation. PEGFIL-mobilized patients were matched by age, disease, and treatment line at a ratio of 1:2 to historical FIL-mobilized controls. The primary study endpoint was the blood CD34(+) concentration at onset of leukapheresis. Leukapheresis began a median of 10 days from the beginning of mobilization chemotherapy in both groups. At the onset of leukapheresis, median blood CD34(+) cell counts did not differ significantly in the FIL group compared with the PEGFIL group (79 x 10(6)/L vs 64 x 10(6)/L, respectively; p = 0.44). In the different disease categories, the respective CD34(+) cell counts after FIL and PEGFIL mobilization were 72 x 10(6)/L vs 123 x 10(6)/L (p = 0.08) in myeloma, 51 x 10(6)/L vs 62 x 10(6)/L (p = 0.6) in lymphomas, and 27 x 10(6)/L vs 30 x 10(6)/L (p = 0.62) in CLL, respectively. The target CD34(+) cell yield was harvested with one leukapheresis in 53% of PEGFIL-mobilized patients. Engraftment after autografting did not differ significantly in the two groups. Stem cell mobilization with a single dose of PEGFIL was, therefore, comparable to that achieved using daily FIL in patients with lymphoproliferative diseases. PEGFIL is a more practical way to mobilize stem cells than daily FIL.