The current study was conducted to evaluate the effects of different levels of Zataria multiflora , Salvia officinalis and probiotics on performance, immunological responses and histological changes of small intestine of laying hen. A total of 225 hen layers of 42 weeks of age were used in completely randomized design the with 9 treatments, 5 replicates and 5 birds each. Dietary treatments consisted of control group(basal diet without additives),0.2 and 0.4% Zataria multiflora , 0.2 and 0.4% Salvia officinalis and 0.4 the mixture of Zattaria multiflora and Salvia officinalis and 0.005 and 0.01% probiotics, that fed during a 80 d feeding trial including 10 days for adaptation and 70 days as main recording period. Performance parameters including feed intake, feed conversation ratio, egg production percentage, egg weight, egg mass and also egg quality were calculated on d 35 and 70 experiment. To investigate immunological response, sheep red blood cells (SRBC) were injected twice (at 10 d intervals. After that, hens were bled at day 6 and 12 after the first and second injection, respectively. Moreover, Newcastel disease virus was injected and then sera were taken at day 6 after injection. In addition, differential leukocyte counts were evaluate at the end of experiment. On 70 day of experiment, two birds of each cage were sacrificed to evaluate the relative weight of internal organs, enumeration of intestinal microbial counts and also jejunal and hepatic morphology. The results showed that using 0.4% of Zataria multiflora increased feed intake (P 0.05) egg production percentage (P=0.07), lymphocyte counts (P 0.05), antibody titer against SRBC (P=0.09), diameter of laminaproperia lymphoid follicles (P 0.01) and egg color index (P=0.06), and also led to a reduction in heterophile to lymphocyte ratio (P=0.09) and also ileum Escherichia coli enumeration (P 0.05). However using 0.4% Salvia officinalis decreased blood glucose levels (P 0.05), serum cholesterol (P 0.05), and Triglyceride (P=0.07) concentrations as well as liver weight (P=0.07). feeding 0.4% of the mixture of Zataria multiflora and Salvia officinalis increased blood HDL (P 0.05), content villus height (P 0.01), crypt depth (P 0.05), liver color density (P=0.06), egg shell weight (P=0.08), egg shell hardness (P 0.05) and Haugh unit (P=0.07). additionally, it decreased enzyme activities of SGOT (P=0.08) and SGPT (P 0.05). On the other hand dietary 0.01% probiotics decreased ALP enzyme activity (P=0.06) and salmonella populations in ileum (P=0.08). In general, our results indicated that dietary inclusion of 0.4% Zataria multiflora led to the best immunological responses and using 0.4% Salvia officinalis modulated serum lipid profile and hepatic enzymes activity؛ however using 0.4% the mixture of Zataria multiflora and Salvia officinalis improved the intestinal histological indices and egg shell hardness. Keywords: Zataria multiflora , Salvia officinalis , Probiotics, Laying hen, Immunological response, Performance