Background: breast cancer (BC) is the most common type of diagnosed cancers in women. It is still the second leading cause of cancer-related death among women after lung cancer all over the world. Breast cancer is the first of top ten cancers in Egypt. It ranks as the first malignancy affecting females, contributing 30% of all female cancers. It affects 1 in 14 women during their life time. Aim: This study investigated the association between cyclooxygenase-2 (COX-2) expression in female breast cancer versus the expression of ER, PR, as well as its association with other established prognostic indicators like age, tumor size, lymph nodal status, stage, grade, lymphovascular invasion, insitu component and histological subtype, and aims to validate the role of overexpression of COX-2 as a prognostic marker in female patients with breast cancer in Egypt. Results: High significant correlation was found between lymph node metastasis, negative ER and PR cases and COX-2 expression. No significant correlation could be detected between age, tumor size, site, histologic type, grade, insitu component, LVI and COX-2 expression. Conclusion: Cyclooxygenase-2 has poor prognostic parameter in breast cancer, as it is over expressed in majority of breast carcinoma, especially with lymph node metastasis, ER and PR negative hormone receptor.