The Epstein–Barr virus (EBV) has recently been identified in human breast cancer globally, potentially contributing to the initiation and progression of this malignancy, as well as gastric cancers, nasopharyngeal carcinoma, and bladder cancer, and has been newly associated with breast cancer. The study aimed to detect the presence of Epstein-Barr Virus Nuclear Antigen-1 (EBNA-1) and encoded RNA (EBER) with tumors of the breast in a group of Iraqi women diagnosed with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) and to correlate expression results with the age of the participants and with the grade, type, size and others clinicopathological finding of breast cancer. A total of 50 formalin-fixed paraffin-embedded tissues from invasive ductal carcinoma (IDC) (92%) and invasive lobular carcinoma (ILC) (8%) biopsy samples constituted the case group, while 30 formalin-fixed paraffin-embedded tissues from non-cancerous breast tissue served as the control group. The presence of Epstein-Barr virus protein (EBER) in breast tissue was assessed using immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) methods. EBER RNA signals were identified in 31 cases (62%). In the control group, EBER RNA signals were identified in 3 (10%) of the subjects. Significant differences (P<0.04) were seen between the research groups for EBV EBER RNA positive signals. The study demonstrated that immunohistochemistry revealed nuclear brown staining in 34 (68%) breast cancer patients. 3 (10%) in the control group. Substantial variations (P<0.03) were seen between the study groups concerning the nuclear brown staining of tumor cell signals. IHC and CISH were identified as sensitive techniques for the identification of EBV. The study concludes that EBNA-1 and EBV EBER RNA were overexpressed in our population group.