Introduction: Tuberculosis remains one of the major communicable diseases. There are number of diagnostic tests available for the diagnosis of tuberculosis but conventional microscopy has low sensitivity and culture although gold standard, takes longer time for positivity. Aim: To evaluate the sensitivity, specificity, PPv & NPV of Nucleic acid amplification assay (GeneXpert) using respiratory samples in patients with suspected pulmonary tuberculosis and compare with AFB smear microscopy and AFB culture. Materials and Methods: 89 patients from April 2015 to July 2017 for ZN stain, culture and GeneXpert (Xpert® MTB/Rif assay) were studied. The sensitivity, specificity, PPV and NPV of GeneXpert and ZN microscopy were calculated using Liquid culture of Mycobacterium tuberculosis as gold standard. Results: A total of 89 patient samples were evaluated in final analysis. Of these, 10 samples were positive by all three methods used in our study. The overall sensitivity, specificity, PPV and NPV of GeneXpert were 86.8%, 93.1%, 78.5% and 96%. The overall sensitivity and specificity of AFB smear microscopy were 22.2%, and 78.5% respectively. Conclusion: GeneXpert can be a useful tool for early diagnosis of patients with high clinical suspicion of pulmonary tuberculosis. The other major advantage of Gene Xpert is that it simultaneously detects Rifampicin resistance and is especially beneficial in patient with MDR and HIV associated tuberculosis and should be studied further.