The aim of the study was to investigate the effect of feeding Japanese quail chicks on diets supplemented with different levels of germinated Moringa Oleifera seed  (GMOS) on productive performance, carcass characteristics and blood constituents. A total number of 252 unsexed seven days-old Japanese quail chicks were randomly distributed to  4 equal groups each containing 63 chicks in 3 replicates with 21 chicks each. Four experimental diets supplemented with GMOS were formulated as follows: 0% (control), 0.25% ,  0.50%  and  0.75% GMOS for 7- 42 days. The results showed that, birds fed GMOS at levels 0.75% followed by 0.50% had significantly higher body weight and body weight gain than birds fed the control diet. The feed consumption  showed  no difference in all treatments. The best feed conversion ratio and European Production Efficiency Index (EPEI) obtained by using 0.75% GMOS compared to control group. Abdominal fat significantly decreased by feeding levels 0.25, 0.50, and 0.75% GMOS respectively compared to the control group. Birds fed on GMOS significantly increased bursa percentages by using all levels of GMOS compared to control group.  Plasma ALT decreased by using 0.75% GMOS compared to control.  However, AST decreased in all levels of GMOS with no difference compared to the control. Plasma cholesterol had lower level in all treatments compared to control group. In addition, HDL fraction was increased and LDL fraction was decreased in all treatments of GMOS. Total antioxidant capacity was significantly increased in group fed 0.50% GMOS compared to other treatments. It could by conclude that using GMOS (0.25, 0.50 and 0.75%) improved performance, immune organs and blood constituents. The best level occurred by 0.75% GMOS in Japanese quails diets during the growing period  (1-42 day).