Objective: To describe the treatment adherence of outpatients with chronic myeloid leukemia at national institute of hematology & blood transfusion. Subjects and Methods: A cross-sectional descriptive study was conducted on 170 outpatients at National Institute of Hematology and Blood Transfusion from January 2022 to June 2022. Results: 98.8% of patients came to the clinic for examination on time. The percentage of patients with drug adherence accounted for 68.8%. There were still many patients who did not comply because they forgot to take the medicine, stopped taking it on their own, and found it difficult to take the medicine. 42.35% of patients had limited knowledge about the disease. Adherence to the diet was relatively good. However, the salt and fat reduction diet was still not well implemented. The exercise regime was still limited, the percentage of people who do exercise occasionally and do not exercise accounted for 50.6%. Conclusion: The rate of patient adherence to treatment was still not high. Interventions are needed to enhance the drug adherence of patients.