Objective: A descriptive and cross-sectional study on quality of life breast cancer postoperative (include both mastectomy and Breast conserving surgery) and dertermine social factors related to quality of life breast cancer postoperative. Method: We collected 60 patients of carcinoma breast cancer post modified radical mastectomy. They were interviewed directly through questionnaires on quality of life of EORTC QLQ C-30. Results: The results showed that the mean age at this study was 47.6 years. Younger women in age group 30-39 years had faird worst on physical, social, and emotional scores as compare to older women in the age group of 70-79 years. Conclusion: The mean socres quality of life of patients with breast cancer postoperative at Thai Nguyen Oncology Center was differencebetween younger patient (30-39) years and older paient (70-79) years. In addi tion, Age and education status on this study were factor which related to quality of life in Breast Cancer Patients.