Background. Exercise is a promising approach in ameliorating the fatigue associated with cancer and its treatment. Design. A randomized design with control, experimental groups being assessed preand postintervention.Methods. Thirty-five patients were randomly selected, with 18 assigned to an exercise group and 17 to a control group. The exercise intervention lasted for 30 minutes every day for six weeks. It consisted of physical exercise combined with relaxation breathing exercise. Fatigue was measured by the revised version of the Piper Fatigue Scale. Results. The exercise group had a greater decrease in fatigue than the control group. Conclusion. These findings indicate that a relaxation breathing exercise would improve fatigue in allogenic haemopoietic stem cell transplantation patients.