The purpose of this study is to investigate how EAC affects the numbers of CD4 T-cells, CD8 T-cells, and activated T-cells in the spleen and PBL. Ehrlich's tumor has historically been used in experimental oncology to evaluate the anti-tumor efficacy of various drugs. However, knowledge of the immunological pathways involved in Ehrlich carcinogenesis is still limited. The study aimed to examine the impact of tumor (EAC) on the total number of T lymphocytes (CD4 / CD8) and activated T cell (CD4⁺CD69⁺ / CD8⁺CD69⁺) populations in the spleen and peripheral blood (PBL). Twelve female albino mice were allocated into two groups: the first was the control (naïve group), while the second was injected interperetonial with 2.5×10^6 EAC. After 14 days of inoculation, blood samples were collected and spleen cells were harvested. Cells were stained with the mAbs and analyzed using Flow Cytometry. In the EAC group, the relative and absolute numbers of CD4 T lymphocytes and CD4+CD69+ T lymphocytes increased compared to the naïve group in the spleen. Additionally, The EAC group showed an increase in the absolute number of CD8 T lymphocytes and CD8⁺CD69⁺ T lymphocytes compared to the naïve group in the spleen. However, the relative and the absolute number of CD4, CD8 T lymphocytes, and CD8⁺CD69⁺ T lymphocytes decreased in the EAC group compared to naïve cells in the PBL. These results could be utilized to enhance cancer treatments, similar to those for Ehrlich's tumor.