Background: Among all types of cancers, breast cancer is the most common and the first cause of cancer deaths in Iranian women, and has prompted important debates today. Moderate to severe symptoms of emotional problems such as depression, sadness, anxiety, irritability, withdrawal from family relationships, anger, fear of death, fear of treatment and its effects and uncertainty about return to health, change in mental image of one's body, and after that, a decrease in psychological health have been reported in these patients. Materials and methods: In a clinical trial, 96 patients with breast cancer were selected after mastectomy surgery at Shahid Motahhari Clinic in Shiraz. They were randomly divided into intervention (n = 48) and control (n = 48) groups. The intervention group received 4 training sessions, while the control group did not receive any intervention. The subjects completed the DASS 21 questionnaire and demographic information during the two stages, before the intervention and two months after the intervention in both groups. Then, their stress, anxiety, and depression levels were analyzed by Kolmograph-Smirnov test (for analyzing normality assumption), paired sample t-test, chi-square test at α = 0.05, or nonparametric analyses were performed. Results: The results of the study showed a significant decrease in the mean stress (P <0.001), anxiety (P <0.001) and depression (P <0.001) after training in the intervention group patients who had referred to breast cancer screening clinic. Therefore, it is suggested that spiritual education should be included as an adjunct plan to the treatment programs of these patients. Conclusion: Spiritual education that aims to influence the stress, depression, and anxiety in patients with breast cancer can reduce stress, anxiety and depression in these patients.