BACKGROUND: Essential oils (EO) are antimicrobial compounds, but may be beneficial under unfavorable nutritional and environmental conditions. Essential oils produced in Iran are of comparable quality to imported ones. OBJECTIVES: The aim of this study was to compare the effects of Orego-Stim (Essential oil based on Oregano; 0.5 g/kg; imported) and Anti-Biophin (Essential oil based on Thyme; 1 g/kg; local) essential oils on performance and precaecal digestibility of nutrients in broiler chicks fed barley-corn based diets with and without b-glucanase (0.05 g/kg). METHODS: At the beginning of the second week of rearing period, 192 chicks of mixed sex were allotted into six groups of four replicates with eight chicks per replicate according to a 2×3 factorial experiment arranged as a completely randomized design. RESULTS: Inclusion of Orego-Stim or Anti-Biophin in barley based diets caused a significant (p<0.05) improvement in total feed conversion, final body weight and nutrients digestibility, without a significant effect of b-glucanase addition to the diets. The type of essential oils (imported vs. local) did not affect the measured characteristics. CONCLUSIONS: Feeding broiler chicks with barley based diets, supplemented with essential oils, decreased the anti-nutritional effects of barley grains in  these diets and improved broiler performance, without the need to supplement the barley-based diets with b-glucanase. Because of the lack of any significant difference between the imported and locally-produced essential oils, and the higher cost and scarcity of the imported EO, domestic products such as Anti-Biophin at recommended levels can replace the imported ones.