Studies applying exercise, relaxation training, and psychoeducation have each indicated a positive impact on physical performance and/or psychological factors in patients diagnosed with cancer. We explored the longitudinal effect of a combination of these interventions on treatment-related symptoms in patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT). Forty-two patients (18-65 years) were randomized either to an intervention or a control group. The intervention group received standard treatment and care, and a supervised four- to six-week structured exercise program, progressive relaxation, and psychoeducation during hospitalization, one hour per day for five days per week. The control group received standard treatment, care, and physiotherapy. A 24-item symptom assessment questionnaire was completed weekly during hospitalization, and at three and six months after allo-HCST. Through principal component analysis with varimax rotation, individual symptoms were grouped into five symptom clusters: mucositis, cognitive, gastrointestinal, affective, and functional symptom clusters. Then, a subsequent general estimate equation analysis revealed similar longitudinal patterns of intensity in all symptom clusters for intervention and control groups, but in the intervention group, there was an overall significant reduction (P<0.05) in symptom intensity over time for all clusters except the affective symptom cluster. This study provides beginning evidence for the efficacy of an exercise-based multimodal intervention in reducing the intensity of a spectrum of symptoms in this small sample of patients undergoing allo-HSCT.