This report examines laboratory and clinical experience with peripheral blood stem/progenitor cell harvest for autografts in 71 consecutively referred children with various types of cancer from one institution. The age of the patients ranged from 7 months to 17 years with a median of 8 years. Ten of the 71 referred children were removed from the collection procedure because of failure to induce clinical remission (nine) or deteriorating chemotherapy-induced liver failure (one). A total of 215 aphereses were performed on a CS 3000 cell separator in 61 patients, including 18 children aged 4 years or less. The methylcellulose progenitor assay was used as an index of stem cell collection. A minimum of greater than or equal to 3 x 10(5) colony-forming units-granulocyte/macrophage (CFU-GM)/kg body weight were collected in 31 of 71 children (44%) with a mean of 3.1 (range, 1-5) aphereses, and greater than or equal to 1 x 10(5) CFU-GM/kg in 46 children (65%). The incidence of serious morbidity was low. When apheresis or chemotherapy was repeated, the progenitor yields decreased rapidly. By multivariate analysis, the age of the patients was the only significant predictor of CFU-GM yield (p = 0.009). In our experience with 12 children with acute leukemia or non-Hodgkin's lymphoma, regimens containing high-dose cytarabine (2.0 g/m2 x 10) were effective for mobilization. Our results extend the earlier findings that harvesting PBSCs for autografts in children with active cancer is a safe and reliable procedure with a low incidence of serious morbidity.