Purpose: The purpose of the study was to identify degrees of pain, menopause symptoms, and quality of life, and to identify factors influencing quality of life of patients with breast cancer who were on hormone therapy. Methods: A cross-sectional survey design was utilized. Data were collected using questionnaires from 110 patients with breast cancer who had been on hormone therapy for 3 months or more and were being treated at a university hospital in Seoul. Data were analyzed using ${chi}^2$-test, t-test, ANOVA, Pearson correlation coefficient and multiple linear regression. Results: Mean age of the participants was 53.56 (SD=6.67) and 54 (51.4%) had stage 0 or I at the time of diagnosis. Most of the participants reported having pain and menopause symptoms (88.2% and 95.5% respectively). The mean score for quality of life was $87.84{pm}21.17$. Pain, menopause symptoms and quality of life had strong correlations with each other (p<.005). Quality of life was explained by menopause symptoms (${eta}$= -.71), economic status (${eta}$=.20) and occupation (${eta}$=.16). Conclusion: The results of the study suggest that menopause symptoms should be incorporated into oncologic nursing care to improve quality of life of patients with breast cancer on hormone therapy.