BACKGROUND: Extracts rich in phenolic compounds have an important role in antioxidant and antimicrobial effects, and pistachio green hull extract is rich in polyphenolic compounds. OBJECTIVES: The aim of this study was to evaluate the effect of green peel of Kalleqouchi and Fandoghi pistachio extract on performance, relative weight of carcass components, blood indices and intestinal microbial population of broiler chickens challenged with Staphylococcus aureus. METHODS: A total 168 one-day-old broiler chicks were randomly divided into six treatments, four replications and seven chicks. Experimental treatments included unchallenged groups (negative control) and chickens challenged with Staphylococcus aureus and fed 0, 200 and 400 mg / kg of aqueous extract of Kalleqouchi pistachio and 200 and 400 mg/ kg of pistachio Fandoghi green extract. All infected chicks were inoculated with oral solution containing 3 x 109 CFU of Staphylococcus aureus. Performance characteristics, immunity, blood indices and microbial population of the intestine were determined. RESULTS: The aqueous extract of green pistachio inhibited the growth of Staphylococcus but the ethanolic extract inhibited the growth of lactobacilli. Growth performance of chicks was not affected by the experimental treatments except at day 24, when aqueous extract of 200 mg / kg led to higher body weight gain as compared to control (0.049). Kalleqouchi extract at 400 mg/kg level increased abdominal fat (P = 0.0005) and had no effect on relative weight of other carcass components. The 400 mg/kg Fandoghi green extract and 200 mg/kg kalleqouchi extract increased enzyme activity of alanine aminotransferase activity and decreased the concentration of blood total protein (P <0.01). The pistachios extracts at all levels increased total antibody titer compared to control (P <0.02). Pistachio extract reduced total bacterial population of jejunal area compared to negative control (P = 0.008). CONCLUSIONS: Application of aqueous extract of pistachio extract improves immune response, decreases blood lipids and intestinal microbial population of broiler chickens challenged with Staphylococcus aureus.