This experiment was conducted to study the effect of probiotic supplement (contains Aspergillus awamori) on performance, egg production, egg quality and serum blood characteristics of quails. A total of 135 laying Japanese quails were randomly assigned to one of five treatments with three replicates (n = 9 quails per replicate). The experimental treatments were: the 1st group received a layer basal diet without supplement and served as control. The 2nd, 3rd, 4th and 5th groups were fed the control diet supplemented with 250, 500, 750 and 1000 mg Tomoko® (contains Aspergillus awamori)/Kg diet for 12 weeks through summer season. Results indicated that the supplementation of 750 and 1000 mg Aspergillus awamori/kg diet recorded a significant (P≤0.05) improvement in egg production by 8.4 and 14.9 % and eggs mass/hen/day (P≤0.05) by 5.0 and 10.7 %, respectively, as compared to the control. However, aforementioned groups improved feed conversion ratio, but differences were not significant compared to the control. No significant differences were observed in feed consumption and most of studied egg quality (egg, yolk and albumen weights, shell percentage, egg specific gravity, albumen index, and yolk index) among treatments. Laying quails fed with 1000 mg of Aspergillus awamori improved albumen height. Inclusion of Aspergillus awamori led to a greater egg shell weight, whereas egg shell thickness was improved in supplemented groups with 250, 500 and 750 mg Aspergillus awamori/kg diet as compared to the control. Yolk total lipids and total cholesterol was decreased significantly and the lowest value was observed in group given 1000 mg Aspergillus awamori/kg diet. Also, birds fed different levels of Aspergillus awamori in diet had serum low density lipoprotein values significantly (P≤0.05) lower than the control. Malondialdehyde (MDA) level of Aspergillus awamori supplemented groups was significantly lower than the control. However results showed insignificant increase in total antioxidant capacity and significant (P≤0.05) increase in glutathione peroxidase in the Aspergillus awamori groups. In conclusion, the results showed that supplementation of probiotic contains Aspergillus awamori improves performance, egg production, and antioxidant status as a feed additive in the diet of laying quails under summer conditions