Although hematologic reconstitution is usually rapid after autologous blood stem cell transplantation (ABSCT), there is an occasional delay in platelet recovery. We studied the hematologic recovery of 27 adult patients with hematologic malignancies who received marrow-ablative chemotherapy and ABSCT to determine whether or not the numbers of infused mononuclear cells (MNC), colony-forming units granulocyte/macrophage (CFU-GM), and colony-forming units megakaryocyte (CFU-Mk) were related to the speed of platelet recovery after ABSCT. Peripheral blood stem cells were collected using chemotherapy-induced mobilization with or without cytokine therapy. While the number of MNC infused did not show a significant correlation with time to platelet recovery as well as granulocyte and reticulocyte recovery, the logarithmic number of CFU-GM-infused did (p < 0.01). We also found a significant correlation between the logarithmic number of CFU-Mk-infused and the time to platelet recovery (p < 0.01). These findings suggest that the number of CFU-GM-infused is a reliable indicator of hematopoietic recovery and that the number of CFU-Mk-infused is no more reliable than CFU-GM for predicting platelet recovery after ABSCT.