Catfish (Clarias gariepinus) is an important aquaculture species, especially in Indonesia. The current obstacle faced by farmers is the attack of pathogenic disease outbreaks which have a negative impact on production and cause economic losses. Therefore, this research was designed to evaluate the immunostimulatory effect of red ginger extract in feed on the hematological and immune responses of catfish. Red Ginger is extracted using ethanol. Phytochemical tests show that red ginger extract contains phenolics, alkaloids and flavonoids. Red ginger extract with various concentrations (50, 100, 150, 200 ppm) was mixed with commercial feed and given to catfish for 14 days of rearing. The results showed that there was no significant effect (P>0.05) on the number of erythrocyte cells between treatments. The same thing happened to total leukocytes in catfish, which did not show a significant effect (p>0.05). However, there was a significant effect (P<0.05) on lymphocytes and monocytes, but not on neutrophils (P>0.05). This research recommends using red ginger extract with a concentration of 150 ppm to improve the hematological performance and immune response of catfish. This research provides new insights into the potential of ginger as an immunostimulant agent in aquaculture.