Breast cancer is a disease that requires palliative care and comfort. The current study aimed to adapt the scale used to assess the comfort level of breast cancer patients receiving palliative care, for the Turkish population, and to contribute to the literature. A total of 340 breast cancer patients who were registered at a university hospital's oncology outpatient clinic, received therapy, and returned for follow-up were included in the study. Data were collected using the Introductory Information Form, Comfort Assessment Breast Cancer Instrument, and General Comfort Scale short form. The International Testing Commission Guide's (2018) suggestions were applied during the scale's modification procedure. The scale's Kaiser Meyer Olkin value was 0.78, and 4454.53 was the Barlett's test result. Fit indices for the confirmatory factor analysis were CFI=0.885, GFI=0.927, and [chi-squared]/df=2.612. The scale's Spearman-Brown correlation value is 0.78, and its Cronbach's alpha coefficient is 0.85. The Comfort Assessment Breast Cancer Instrument's Turkish version provides a reliable and valid tool for assessing the comfort of breast cancer patients. The use of it can help determine the comfort level of breast cancer patients receiving palliative care and inform the development of interventions and care practices throughout each stage of the disease. [Note: The page range (33-44) shown on the PDF is incorrect. The correct page range is 33-45.]