The increased interest in new approaches to the immunotherapy of cancer and a considerable demand for therapeutic agents which can modulate the several forms of immunodeficiency have encouraged studies on the immunomodulatory mechanisms of natural and synthetic substances. The present work was an endeavor to evaluate the imunostimulating as well as proapoptotic and synergistic effects of Chrysin (Ch) and Propolis (P) on the tumor growth and the cell sensitivity to ionizing radiation targeting the improvement of cancer therapeutic protocols. Chrysin (20 mg/kg body weight/day) and Propolis (100 mg/kg body weight day) were injected intraperitoneal to mice bearing 1cm³ solid tumor of Ehrlich ascites carcinoma (EAC) for 21 consecutive days. Mice were whole body exposed to 1 Gy of gamma radiation (two fractionated doses at 11 and 25 days post EAC inoculation, respectively). Treatments with Ch or P markedly suppress the proliferation of tumor in mice bearing solid Ehrlich tumor (EAC mice). The activity of interferon-gamma (IFN-γ) was significantly decreased in the treated mice compared to EAC mice. The concentrations of m-RNA for angiogenic factor (tumor necrosis factor alpha -TNF-α), free radicals as well as nitric oxide (NO) concentration were significantly decreased collimated with improvements in apoptotic regulators (Caspase-3 activity) compared to EAC mice.  Moreover, the histopathological investigation confirms the improvement exerted by Ch or P even in EAC mice group or mice bearing solid Ehrlich tumor and subjected to γ-irradiation (EAC+R group). Exposure to gamma radiation sustained the modulatory effect of Ch or P on tumor when compared with EAC mice and those injected with Ch (EAC+Ch) or EAC and injected with P (EAC+P). Hence, Ch or P might represent a potential therapeutic strategy for increasing the radiation response of solid tumor.