PURPOSE: To investigate the effects of dynamic-static combined relaxation therapy on fatigue and sleep disorders in breast cancer patients undergoing chemotherapy. METHODS: A total of 114 patients receiving chemotherapy at Tangshan People's Hospital (September 2023-June 2024) were randomly divided into three groups: control (routine nursing), experiment group 1 (static Benson relaxation), and experiment group 2 (dynamic yoga + static Benson relaxation). The intervention lasted 8 weeks. Cancer-related fatigue and sleep disorders were assessed before and after intervention using the Revised Piper Fatigue Scale and the Pittsburgh Sleep Quality Index (PSQI). RESULTS: Prior to intervention, there were no significant differences in fatigue and sleep quality across groups (P > 0.05). Post-intervention, both experiment groups showed significant improvements in fatigue and sleep quality compared to the control (P < 0.001). Experiment group 2 showed greater reductions in behavior, body, and total fatigue scores compared to experiment group 1 (P < 0.001). Sleep quality also improved significantly in both experiment groups, with experiment group 2 demonstrating superior outcomes in sleep quality, duration, daytime dysfunction, and total PSQI score (P < 0.05). CONCLUSION: The Benson relaxation technique and dynamic-static combined relaxation therapy are effective in reducing fatigue and improving sleep quality in breast cancer chemotherapy patients, with the dynamic-static combined relaxation therapy offering greater benefits. TRIAL NUMBER: RMYY-LLKS-2024068.