Purpose: The aim of this study was to investigate the differences in quality of life in patients who received breast conserving surgery (BCS) or modified radical mastectomy (MRM) for breast cancer. Materials and Methods: A total of 100 women with breast cancer who underwent either BCS or MRM between September 2011 and April 2012 at a private health center and completed their chemotherapy and radiation therapy cycles were included in the study. To assess the quality of life, we used a demographic questionnaire, the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and the Quality of Life assessment in Breast Cancer (EORTC QLQ-BR23). Results: Using QLQ-C30, we found that patients who underwent BCS had better functional status and fewer symptoms than patients who underwent MRM. In QLQ-BR23, independent factors improving the functional scales were BCS, higher level of education and marital status (married); independent factors improving symptoms were BCS, higher level of education, younger age and low and normal body mass index (BMI). In QLQ-C30, independent factors affecting the functional and symptom scales were only BCS and higher level of education. Conclusions: We determined that patients who received BCS had better functional status and less frequent symptoms than patients who underwent MRM.