Caprylic acid (CA) and Yucca schidigera (YS) extract have much functional and nutritional properties that may have uses in poultry feeding. These beneficial effects include improvement of productive perfor­mance, egg quality immunity, hormones and other blood parameters. This study was conducted to evaluate the effects of dietary supplemen­tation with different levels of CA with constant level of YS extract on productive performance, immunity status and some blood characteristics in laying hens. A total number of 120 Lohmann Brown hens 24 weeks old were used in this experiment. The hens were randomly distributed into 8 experimental groups and each group was divided into five replicates three hens each and dietary treatments can describe as follows : (T1): control diet (basal diet without supplement). (T2): basal diet with 100 mg/kg feed of Yucca schidigera extract. (T3): basal diet with 500 mg/kg feed of caprylic acid. (T4): basal diet with 100 mg/kg feed of Yucca schidigera extract + 500 mg/kg feed of caprylic acid. (T5): basal diet with 1000 mg/kg feed of caprylic acid. (T6): basal diet with 100 mg/kg feed of Yucca schidigera extract + 1000 mg/kg feed of caprylic acid. (T7): basal diet with 2000 mg/kg feed of caprylic acid. (T8): basal diet with 100 mg/kg feed of Yucca schidigera extract + 2000 mg/kg feed of caprylic acid. Results showed that supplemented laying hen diets with CA and YS were significant differences and led to improve the BW, FI, FCR, egg production and egg mass among the dietary treatments. The egg quality parameters such as egg weight, yolk weight, albumin weight, eggshell weight, eggshell thickness, yolk index, shape index and yolk color in this study were not significantly affected by supplementation of layer chicken diets with different level of CA and YS. The concentration of serum glucose was significantly (P≤0.05) increased in all groups compared to control group. Also, the concentration of T₃ and T₄ hormones in serum was significantly (P≤0.05) increased as the level of CA increased in the layer diets with or without YS compared to control group. While, serum total cholesterol concentrations were significantly (P≤0.05) decreased as utilization level of CA increased either alone or with YS in the layer diets. The results of H/L ratio were significantly (P≤0.05) decreased as the level of CA increased in the layer chicken diets specially groups of T7 and T8. The rest of biochemical parameters such as serum IgG, serum total protein, serum albumin and serum globulin The results of these mentioned parameters in this study revealed that dietary inclusion of CA and YS significantly (P≤0.05) increased concentrations of that parameters as the level of CA increased in the hen diets. Therefore, it is recommended to applicate both of CA and YS in layer chicken diets at levels studied without any adverse effect on productive and immunity status of layer hens