Background: female mammary carcinoma is the second most common cancer incidence among women and the fifth most common leading cause of cancer death worldwide. Premenopausal young women are more frequently targeted by inflammatory breast cancer (IBC), which is the most lethal form of breast cancer. The human cytomegalovirus (HCMV) has been identified as one of the viral infection with a higher frequency in carcinoma tissues of IBC than in non-IBC. The adaptor protein growth factor receptor-bound protein 2 (Grb2), was found to be upregulated in HCMV-infected cells and play as crucial role in cancer progression. Objective: this study aimed to assess the expression level of Grb2 in carcinoma tissues of IBC and non-IBC with HCMV infection. Patients and Methods: overall, 135 female diagnosed with breast carcinoma were enrolled in this study. Using conventional and real time polymerase chain reaction (PCR), we determined the incidence of HCMV and assessed the expression level of Grb2 mRNA in the breast cancer tissue samples. Results: Grb2 mRNA was significantly upregulated in HCMV+ IBC higher than in HCMV+ non-IBC. According to the molecular subtype, Grb2 mRNA was significantly higher upregulated in breast carcinoma tissues of HCMV+ hormonal positive (HP) than in triple negative (TN) counterparts. Conclusion: HCMV infection is associated with a high expression of Grb2 mRNA in IBC and that HP HCMV+ mammary carcinoma tissues confer upregulated Grb2 mRNA, suggesting a potential role of HCMV infection in enhancing of Grb2 mRNA expression in breast cancer with HP.