Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) is increasingly used in the treatment of hematologic cancers such as leukemias, lymphomas, and myeloma, and for other hematologic disorders such as primary immunodeficiency, aplastic anemia, and myelodysplasia. Allo-HSCT entails a conditioning regimen of frequent high-dose chemotherapy in combination with total body irradiation, followed by infusion of donor-harvested bone marrow or peripheral blood stem cells. As an aggressive and demanding medical therapy that profoundly impacts patient quality of life (QOL), allo-HSCT is associated with numerous treatment-related physical, psychological, and psychosocial side effects. The procedure can result in decreased respiratory and balance function, skeletal muscle strength, and exercise capacity. Thus, as physical exercise has been shown to positively effect physical and psychosocial function and QOL in allo-HSCT patients, it is a recommended intervention for improving essential functions and offsetting lost exercise capacity after the procedure. Furthermore, recent evidence has shown that physical exercise can influence survival rate and mortality in allo-HSCT patients. This review provides an overview of the current research on the effectiveness of physical exercise for allo-HSCT patients.