Background and Objectives: ESBLs are the lactam antibiotics hydrolyzing enzymes playing major barriers in employing lactam antibiotics to treat TB infection. In this study, we evaluated ß-lactam antibiotics either pure or in combination with clavulanic acid for their Mycobacterium tuberculosis growth inhibiting potential by nitrate reductase assay which utilizes the detection of nitrate reduction as an indication of growth. Methods: 100 AFB-Positive sputum samples collected from different clinical settings in district Saharanpur (U.P.) of India and H37Rv control strain was used as a control. Clinical isolates of M. tuberculosis were tested for six ß-lactam antibiotics either pure or in combination with clavulanic acid by Nitrate Reductase Assay (NRA) and were compared with standard proportion method. The bacteria were inoculated on Lowenstein-Jensen (LJ) medium with ESBL drugs and potassium nitrate was incorporated. After incubation for a period of 10 days to 20 days, the mycobacterial growth was detected by color change due to nitrate reduction when reagents were added. Results: All the clinical isolates of M. tuberculosis showed resistance for piperacillin, carbenicillin, mezlocillin, ticarcillin, ceftriaxone, and cefotaxime when used alone but the growth of M. tuberculosis isolates was significantly decreased when used in combination with the clavulanic acid. Complete agreement (100%) was found for ß-lactam antibiotics with clavulanic acid. In contrast to proportion methods usually which takes 4weeks to 6 weeks LJ Culture method, the drug susceptibility results by NRA could be observed within 10 days to 20 days. Interpretation and Conclusion: The ESBL resistance in all the M. tuberculosis clinical isolates was proved and significant growth inhibition of M. tuberculosis was observed when ß-lactam antibiotics in combination with the clavulanic acid. The results of susceptibility were obtained as early as 7 days to 10 days by NRA. This also proved that NRA could be an appropriate alternative to testing M. tuberculosis drug susceptibility in a clinical setting with only very basic testing facilities.