The antiviral activity of Curcuma longa against NDV on vero cell culture and in infected chicken was observed. The obtained results showed that low concentration of Curcuma longa 0.25% did not produce cytotoxicity on the vero cell. The effect of Curcuma longa on NDV titre was studied and the results revealed clearly that chickens treated with 1% Curcuma longa as Prophylactic also showed higher protection rate (90%), the chickens that treated with 0.5 % Curcuma longa showed protection rate (80%).Chicks that infected with NDV without treatment with Curcuma longa showed lower protection rate (8%). The chickens infected then treated with 1% Curcuma longa showed protection (65%) and the chickens infected then treated with 0.5% Curcuma longa showed protection (40%).