Abstract: The current research investigated the growth performance, hematology, serum biochemistry of Japanese quails fed Neem (Azadirachta indica) and Tulsi (Ocimum sanctum) leaves powder with basic diet. A total number of 300 one-week old Japanese quail chicks were divided randomly into four dietary treatments with five replicates each (15 birds per replicate). Dietary treatments were: T0 or control or basal diet, T1 (Neem 0.5%), T2 (Tulsi 1%) and T3 (Neem 0.25% + Tulsi 0.5%) in basal diet. Growth performance parameters (feed intake, body weight, weight gain and feed conversion rate) were determined weekly. Hematology, serum biochemistry, carcass traits were evaluated on 35 days of the age. Neem and Tulsi alone and their combination as a dietary supplement, significantly (p ≤ 0.05) increased the body weight and body weight gain. The combination of Neem and Tulsi also resulted in significantly lower FCR. Carcass traits were significantly (p ≤ 0.05) better in T3 except for the liver weight that was nonsignificantly (p > 0.05) different among the treatment groups. Hemato-biochemical parameters (glucose, hemoglobin, WBCs, MCH, total cholesterol, HDL and LDL cholesterol, total protein) were different significantly different (p ≤ 0.05) among the treatment groups. However, RBCs, HCT, MCV, MCHC, platelets, triglycerides and VLDL were not affected by herbal treatments (p > 0.05). It was concluded that a combination of leaves ‘powder of Neem and Tulsi can be used for improving the growth performance, carcass traits and health of the Japanese quails.Key words: Body weight, blood profile, meat yield, herbal diet, health