In this study, the antibacterial effects of nitric oxide (NO) have been investigated against 4 strains of multidrug-resistant Mycobacterium tuberculosis and 8 Klebsiella, 7 Escherichia coli, 7 Staphylococcus, 5 Enterobacter, 7 Pseudomonas and 7 Proteus clinical isolates by using DETA-NO ((Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate) as the NO donor. Minimum inhibitory concentrations (MICs) were determined by broth microdilution method for all tested microorganisms. The MIC values found in our study were as follows; 0.25 mg/ml for all of the multidrug-resistant Mycobacterium tuberculosis strains, 1 mg/ml for Staphylococcus strains, and approximately 2 mg/ml for the rest of the bacterial strains. These results showed that NO (or NO donor DETA-NO) was more effective on multidrug-resistant M. tuberculosis strains than the other bacterial species. It can be concluded that further studies are needed to explain the clinical use of NO donor DETA-NO, especially, in patients infected with multidrug-resistant M. tuberculosis.