Background and aim: Breast cancer is the commonest malignant tumor and a common cause of cancer death in women all over the world. Some recent studies attributed breast cancer to viral infection. This study aimed to evaluate the expression of HCMV, EBV and HPV in invasive carcinoma of the breast among the Egyptian women by immunohistochemistry and whether there is a relationship between the prognostic factors of breast carcinoma and these viruses. Patients and methods: This retrospective study included 107 selected cases of invasive breast carcinoma. Slides cut from tissue microarray prepared blocks were stained immunohistochemically for HCMV, EBV and HPV antigens. The association of such viruses with the clinicopathological features, tumor recurrence and patient death was evaluated statistically. Result: HCMV, EBV and HPV were present in 43.9%, 10.3% and 24.3% of cases respectively. HCMV was associated significantly with the tumor grade, mitotic count (P = .01), IDC, ER, PR, Her2/neu and molecular subtype (P = .032, .002, .02, .005, .003) respectively. EBV was associated with the tumor size, stage and histological type (P = . 025, .005, .009) respectively. HPV wasn't associated with any of the clinicopathological characteristics. None of these viruses was associated with the tumor recurrence or patient death. Conclusion: HCMV and EBV might be contributing factors for the development and behavioural alteration of breast carcinoma, representing potential tools for the detection of specific therapies for this cancer. Further studies on a larger number of cases using other techniques such as CISH for specific typing of the viruses especially HPV can add more information.