Blood and Marrow Transplant Clinical Trials Network (BMT CTN) protocol 0902 evaluated whether exercise and stress management training before hematopoietic cell transplantation (HCT) improved physical and mental functioning after HCT. Neither overall survival nor other patient-reported transplantation outcomes were improved by the training intervention. In some animal studies of HCT, moderate-intensity exercise for 8 weeks before HCT has been associated with positive effects on hematopoietic progenitors, resulting in improved donor engraftment and improved survival. Accordingly, we performed a secondary analysis of data from BMT CTN 0902 to determine whether exercise engagement before HCT was associated with engraftment and survival. We found no significant associations between self-reported pre-HCT exercise levels and engraftment or survival. There was also no effect of pretransplantation exercise on either neutrophil or platelet engraftment. These findings do not support the observations in animal models but are limited by several shortcomings that do not refute the hypothesis that exercise before HCT may be beneficial. (C) 2017 American Society for Blood and Marrow Transplantation.