OBJECTIVE: The objective of this study was to identify the level of anxiety, stress and depression in breast cancer patients undergoing chemotherapy. METHODOLOGY: This cross -sectional study was conducted in Banda Aceh City, Indonesia. The total population of breast cancer patients undergoing chemotherapy during September 2023 was used as a sample, making the sample size 60 respondents. The data collection tool was the Depression Anxiety and Stress Scale 42 (DASS -42) questionnaire. Independent t -test was used to examine the difference in anxiety scores at the second measurement in the intervention and control groups. RESULTS: Sixty percent were pre -elderly or 45 -59 years old, with secondary education 53.3%, Aceh ethnicity 81.7%, married 73.3%, working 66.7%, fifth chemotherapy cycle 38.3%, and 58.3% menopausal women. A total of 43.3% in moderate level anxiety, moderate level stress, 33.3%, and 46.7% mild level depression. CONCLUSION: The most significant frequency of anxiety is moderate level, stress is moderate level, and depression is mild level depression. Recommendation for hospital: a multidisciplinary approach is needed to reduce anxiety, stress and depression. Nurses are expected to develop appropriate interventions, including a culture -based approach.