BACKGROUND: Mindfulness-based art therapy (MBAT) induces emotional relaxation in cancer patients and is a treatment known to improve psychological stability. The objective of this research was to evaluate the treatment effects of MBAT for breast cancer patients. METHODS: Overall, 24 breast cancer patients were selected as subjects of the study. Two groups, the MBAT group and control group with 12 patients each, were randomly assigned. The patients in the MBAT group were given 12 sessions of treatments. To measure depression and anxiety, low scales of the personality assessment inventory (PAI) was used. Health-related quality of life was evaluated using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTCQLQ-C30). The treatment results were analyzed using analysis of covariance (ANCOVA) and two-way repeated measures analysis of variance (ANOVA). RESULTS: The results showed that depression and anxiety decreased significantly and health-related quality of life improved significantly in the MBAT group. In the control group, however, there was no significant change. CONCLUSIONS: MBAT can be seen as an effective treatment method that improves breast cancer patients׳ psychological stability and quality of life. Evaluation of treatment effects using program development and large-scale research for future clinical application is needed.