The present study was carried out to investigate the effect of dietary supplementation of two cold pressed oils and their combination on productive performance, carcass traits and some blood parameters of growing Japanese quails. A total number of 400 chicks of unsexed one week old Japanese quail were distributed into four dietary treatment groups according to diets fed as; (T1) fed basal diet (BD) representing the control; (T2) fed BD + Thyme Oil (TO) 250mg/ Kg; (T3) fed BD + Marjoram Oil (MO) 250 mg/ Kg and (T4) fed BD + TO 125 mg/Kg plus MO 125mg/Kg. Each treatment comprised of 100 chicks in 5 replicates of 20 chicks each. Results showed that groups fed diets supplemented with thyme or its combination with marjoram oil exhibited significantly better (P≤0.01) live body weight (LBW) at 3 and 6 week of age as well as body weight gain (BWG) through 1-3 and 1-6 week of age (P>0.01), comparing with that of control or marjoram groups. Daily feed intake (DFI) showed no significant (P>0.05) differences among different groups. However, feed conversion (FC) values demonstrated no significant variation among dietary treatments during 1-3 and 3-6 weeks of age, while results of the whole period, 1-6 weeks of age, indicated significant (P≤0.01) enhancement of FC due to dietary supplementation of thyme oil and its combination with marjoram comparing with control or marjoram groups. All carcass traits were not significantly affected by different dietary treatments. The experimental groups had no significant effect on plasma total protein, albumin, globulin, albumin/globulin ratio and aspartate aminotransferase (AST) while, alanine aminotransferase (ALT) values were significantly reduced due to treatments of cold pressed oils comparing to control treatment. In conclusion, supplementing marjoram and thyme cold pressed oils into the Japanese quails improved productive performance without any detrimental impacts on blood parameters.