Bone marrow is currently regarded as the most appropriate source of stem cells for patients with acute myeloid leukemia (AML) undergoing autologous transplants. A total of 55 adult patients with AML in first complete remission receiving autologous bone marrow-derived stem cell (BMSC) transplantation (BMSCT) were analyzed to determine factors affecting the rate of neutrophil recovery. All patients were treated with standard induction and three to four courses of consolidation chemotherapy and, after collection of BMSC, conditioned with BuCy2. The median time to neutrophil reconstitution was 30 (10-62) days and was delayed in 24 patients. Neutrophil recovery was faster in patients who had received granulocyte-macrophage progenitors (CFU-GM) dose >23.5 x 10(4)/kg, CD34(+) cells >3.2 x 10(6)/kg, and mononuclear cells (MNCs) >3 x 10(8)/kg. The speed of neutrophil recovery correlated with the number of transplanted CFU-GM progenitors (P = .0077) and MNCs (P = .0015). CFU-GM progenitors dose was the only factor close to significance in univariate analysis of neutrophil engraftment. Probability for neutrophil recovery was higher in patients transplanted with a higher dose of MNCs. These data suggested that the content of CFU-GM progenitors and MNCs within the bone marrow graft was the most important factor for the quality of neutrophil recovery after autologous BMSCT in AML patients.