Mastectomy is a breast cancer surgical therapy that can lead to permanent changes in a womanâ€™s appearance. This change can cause negative changes in a womanâ€™s self-concept. If the disruption of self-concept continues, it will cause emotional weakness. Individuals will be depressed and feel anxious continuously, emotional frustration is getting worse, making individuals create self-destruction. For this reason, therapy is needed that can overcome this negative self-concept problem from Emotional Freedom Technique (SEFT) Spiritual Therapy. The aim of this study was to identify the effects of SEFT therapy on self-concept in women with breast cancer with a mastectomy. This study used a quasi-experimental design with one group pretest-posttest design approach with inclusion criteria willing to be a research subject, aware, no hearing loss or cognitive impairment of self-concept, never had SEFT therapy, interacted with family and community at least 1 week after mastectomy . This therapy was carried out for 3 days in 33 subjects. Data were analyzed by Chi square statistical test with 95% CI with a significance of p <0.05. The results of this study were before given SEFT treatment from 33 respondents, there were 4 respondents (12.1%) who had a positive self-concept, and the majority of 29 respondents (87.9%) had negative self-concept. After SEFT treatment there was an increase in self-concept of respondents with positive self-concept as many as 10 people (30.3%) and still had negative self-concept as many as 23 people (69.7%). The results of the analysis showed that there were differences in self-concept before and after SEFT with a value of p = 0.05. Nurses are encouraged to exercise this ability and use this therapy as a therapy to prevent self-concept disorders in breast cancer patients with mastectomy.