PURPOSE: The purpose of this study was to identify the relationship between the degree of support from the spouse and the degree of health promoting behavior among the patients with a mastectomy or both mastectomies. METHODS: This study used a descriptive research design. The Participants with a mastectomy or both mastectomies were 224 patients. Data were collected though a structured questionnaire from June to October, 2013. The utilized measurements were Support of Spouse and The Health Promoting Life Profile II. The data were analyzed using descriptive statistics, t-test, ANOVA, and Pearson's correlation coefficients. RESULTS: The mean scores in support of spouse (3.69+/-0.91) and health promoting behavior (2.89+/-0.48) by perception of patients with mastectomy were moderate. The degree of support from the spouse was positively related to five health promoting behaviors; spiritual growth (r=.54, p<.001), stress management (r=.47, p<.001), health responsibility (r=.31, p<.001), interpersonal relations (r=.32, p<.001), nutrition (r=.16, p=.017), except physical activity (r=.09 p=.184). CONCLUSION: It is necessary to educate patients and their spouses about health management after mastectomy to overcome long-term treatment and to improve the quality of life for the patient and spouse.