Background: Obesity is a modifiable risk factor for breast cancer in postmenopausal females. Objective: This study was conducted to investigate the association between obesity and breast cancer risk among Egyptian postmenopausal females in Alexandria. Subjects: This study included 100 Egyptian postmenopausal females, 50 of them were breast cancer patients with mean age (54.6 years± 9.6) and the other 50 were controls with mean age (53.9 years± 2.5). Methods: Standardized questionnaires concerning age, anthropometric, menstrual and reproductive information, family history of breast cancer in first degree relatives and history of hypertension were completed by the same researcher. Fasting blood samples were withdrawn from all participating females to separate sera in which total estradiol, insulin and glucose levels were measured. Results: Univariate analysis showed that age at presentation ≥ 60 years, delayed menopause > 50 years, family history of breast cancer in first degree relatives, oral contraceptive use, body mass index (BMI), waist circumference (WC) and serum levels of total estradiol were found to be significantly associated with higher risk of breast cancer in postmenopausal females.  Multivariate logistic regression analysis showed that old age at presentation ≥ 60 years and late menopause >50 years were the strongest risk factors, while oral contraceptive use and increased WC >100 cm showed border line significance. Conclusion: Based on the results obtained from this study, we advice Egyptian postmenopausal females of Alexandria to control weight by decreasing dietary caloric intake, maintain physical activity and breast self-examination continuously in order to decrease the risk of breast carcinoma.