Background: Cancer-related Fatigue (CRF) is one of the most common complications of acute myeloid leukemia(AML) and its related therapies. It can influence all physical and psychological aspects of the patient’s life. Also, itis believed that exercise can improve CRF in patients with cancer. Objective: This study aimed to investigate theeffect of the walking exercise program on CRF in patients with AML undergoing chemotherapy. Methods: In thisquasi-experimental study with a pre- and post-test design, 50 patients with AML undergoing chemotherapy wereselected using a convenience sampling method at a teaching hospital in an urban area of Iran. The intervention includeddaily 30 minutes of planned walking for ten days. Data was collected using a demographic data form and the BriefFatigue Inventory, which were filled out before the intervention, and on the fifth and tenth days of the intervention.Findings: Statistically significant differences were reported in the reduction of CRF on the fifth day and tenth dayof the intervention (p <0.001). Conclusions: The planned walking intervention can be used as an easy and low-costmethod for reducing CRF in patients with leukemia.