This study was conducted to evaluate the effect of a dietary mixed medicinal herbs powders (MHPs) (Thymus vulgaris, Pennyroyal, Cumin, Alhagi, Garlic and Eucalyptus globules) on performance, egg quality and immunity response of laying hens. The experiment was carried out under completely randomized design, including five treatments (Treatment 1= basal diet without additive (control group), Treatment 2= basal diet + probiotics at 0.1%, T3, T4 and T5=basal diet +1, 2 and 3% MHPs respectively) with five replicates (12 birds each replicate). 300 Bovans laying birds (49 wks old) were distributed randomly in cages and allotted into one of experimental diets for 84 days. The performance was recorded every week. In order to examine the antibody against the sheep red blood cell (SRBC), 2 piece of hen from each replicate was randomly chosen (1cc) SRBC (%0.5) was injected and ten days later blood samples were collected. To examine the blood parameters (Serum Cholesterol, Red blood cells, White blood cells, Lymphocyte, Packed cell volume), In the day 70th , from each replicate 2 piece of hen blood samples was taken. Egg quality parameters (High unit, specific gravity, shell weight and thickness and yolk cholesterol) at the end of the experiment were evaluated. Diets supplemented with 1, 2, or 3% MHPs had no significant effects on percentage of egg production, egg weight mass, and feed conversion ratio (FCR). However, at the level of 2 and 3%, daily feed intake decrease significantly (P< 0.05) compared to the control, probiotic and 1% MHPs. Probiotic and different levels of MHPs had no significant effect on SRBC. Probiotic and 1 and 2% MHPs significantly (P < 0.05) decrease IgG in compare to control and 3% MHPs. Using probiotic in the diet significantly increase IgM in laying hens in compare to control and different levels of MHPs. Probiotic and levels of MHPs had no significant effect on egg weight, shell weight, shell thickness, specific gravity and haugh unit and serum cholesterol. However, MHPs at the level of 1% increase yolk cholesterol in compare to probitic, control, 2 and 3% MHPs significantly. In conclusion, using medical herbs in mixed form may suppress positive effect of medical herbs in compare to using individually.