Objectives: This research was done for comparision the effect of satureja hortensis extract and thymus vulgaris extract with antibiotic growth prompter (AGP) on some immune parameters of broilers. Materials & Methods: In this study 200 Ross broiler chicks broiler chicks in a completely randomized design with 5 treatments and 4 replicates of 10 chicks were tested. Treatments involved control group the basal diet، basal diet plus 0.45 percent of the antibiotic growth promoter AGP, basal diet with 0.05 percent satureja hortensis extract, basal diet with0.05 percent thymus vulgaris extract ،the basal dietplus 0.025and 0.025 percent of the satureja hortensis extract and thymus vulgaris extract In 28 and 35 days of age 0.5ml of sheep red blood cells (SRBC) was injected in breast muscle of 2 birds from each replicated. On the final day (42 day) of the study, 2 birds from each replicat randomly was selected that taked blood samples for analysis blood cells and killed for determination of proportional weight of bursa of fabricius, thymus and spleen. Results & Conclusion: The results of this study showed that There were no significant difference between the treatments for proportional weight of thymus and spleen (p >0.5). the bursa of fabricius weight had significantly difference between treatments (p<%5). The SRBC injection had no significant effect on the weight of the thymus, spleen and bursa of fabricius (% 5
