BACKGROUND: The successful mobilization and collection of hematopoietic stem cells are dependent on a number of clinical factors such as previous chemotherapy and disease stage. The aim of this retrospective study was to determine whether the effectiveness of mobilization and collection is an independent prognostic factor for autologous stem cell transplantation outcome. STUDY DESIGN AND METHODS: A total of 358 patients who received transplants from January 2003 to December 2004 (201 male and 157 female patients, ages from 2.7 to 77.3 years with median of 53 years of age) underwent autologous hematopoietic stem cell collection after mobilization with granulocyte-colony-stimulating factor (G-CSF) or G-CSF plus chemotherapy priming. This retrospective study included patients with diagnoses of acute myelogenous leukemia, non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, and solid tumors. All patients underwent stem cell collection until a target or a minimum CD34+ cell dose was reached. Correlations were performed between stem cell mobilization and/or collection efficacy and transplantation outcomes. RESULTS: In general, both larger reinfused CD34+ cell dose and shorter number of days for the stem cell count to reach the minimum of 2 × 106 per kg CD34+ cells do not foster quicker engraftment. Reinfused CD34+ cell dose of less than 12 × 106 and number of days stem cell collection to reach this minimum CD34+ cell dose did not independently affect the overall survival (OS) or disease-free survival (DFS). CONCLUSION: The effectiveness of hematopoietic stem cell mobilization and collection as defined as number of days to reach a CD34+ cell dose of 2 × 106 per kg should not be used independently to forecast posttransplantation prognosis, engraftment, DFS, and OS. © 2007 American Association of Blood Banks.