Background: Mycobacterium tuberculosis complex is the causative organism of tuberculosis, it is a major health problem throughout the world. In developing countries like India, almost 25% of adult deaths which are avoidable are caused by it. Around 22-61% of Cases have smear negative but culture positive state where clinical profile and radiological lesions suggest diagnosis of pulmonary tuberculosis, then initiation of antitubercular drugs is not advisable without meticulous search for tubercular bacilli. Gold standard for diagnosis of tuberculosis is culture of sputum, but it takes long time( 45 days ) to perform.