The effects of Trigonella foenum graecum (TF) and Foeniculum vulgare (FV) seeds powder on antimicrobial activity and performance of broiler chickens were studied. Based on a completely randomized design, 240 broiler chicks (Ross 308) were assigned to 4 treatments and 4 replicates. The treatments were a basal diet (control, T 1), T 1 plus 0.5% TF (T 2), T 1 plus 0.5% FV (T 3) and TFFV (0.25% TF+ 0.25% FV)(T 4). The diets fed to birds during a 1-42 days period. Treatments containing medical plants showed better performance and lower total number of bacteria (TNB) and Coliform compared to the control (P< 0.05). The presence of salmonella was negative in all tested samples. The weight and length of small intestine and carcass yield in birds fed medicinal plants were higher than those of control (P< 0.05). Therefore, the results of this study showed that the use of medicinal plants can improve performance and health conditions in broiler chicks.