Aim: This study investigated the immunomodulatory and anti-tumor effects of Nigella glandulifera Freyn and Sint seeds (NGS) on Ehrlich ascites carcinoma in a mouse model. Materials and Methods: Kunming mice with transplanted Ehrlich ascites tumor cells (EAC) were treated with NGS by oral administration. On the 11 th day after the EAC implant, mouse thymus, liver, spleen and kidney tumors were removed for histopathological analysis. Blood samples were taken for hematological and biochemical analyses. Results: The results indicate that NGS treatment leads to an increase in TNF-α, IL-1β, and IL-2 blood serum levels. Absence of viable EAC and presence of necrotic cells were observed in the tumor tissue of the NGS-treated animals. Conclusions: The study results indicated that a water extract of NGS had the highest anti-tumor effect. Moreover, NGS treatment also showed an increase in the immune system activity.