Abstract Background and purpose: Ethambutol (EMB) is one of the first - line drugs used for anti-tubercular therapy but resistance to this medicine is developed in many parts of the world. EMB resistant strains commonly have embB mutations. Purpose of this research was detection of EMB-resistant Mycobactercium tuberculosis strains isolated from patients by MAS-PCR method and comparison with Proportion procedure.Materials and Methods: One hundred and twenty M. tuberculosis strains were isolated from patients with tulerculosis in Tabriz TB research center. Susceptibility testing to EMB was performed by the Proportion method. DNA was isolated from cultivated cells by SDS-proteinase K modified method. Isolated DNA was used as the template for PCR reaction.Results: One hundred and sixteen strains were susceptible to EMB and 4 (3.33%) strains were resistant to EMB. All EMB resistant strains were multidrug-resistant. The MAS-PCR method was used to evaluate of mutation in the embB306 codon. Mutation was seen at the embB306 codon in all resistant strains to ethambutol.Conclusion: The results showed that MAS-PCR method can be used as a simple and rapid procedure for detecting EMB-resistance in Mycobacterium tuberculosis strains.