Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (MTB).The disease primarily affects lungs and causes pulmonary tuberculosis. It can also affect intestine, bone, meanings, joints, lymph glands, skin and other tissues of the body. The disease is usually chronic with varied clinical manifestations.The early diagnosis of these bacteria is very essential because of its fatal pulmonary and extrapulmonary manifestations. Many methods have been developed for their detection, but most of these methods take at least six weeks for detection. The nucleic acid based methods have made the detection in short time with high sensitivity and specificity when interpreted with other supplementary tests for MTB detection.Nucleic acid based technologies such as PCR offer great promise for the rapid diagnosis of tuberculosis in situations where conventional approaches fail because of lower bacterial load of bacilli which do not get detected in smear examination. Numerous genetargets for PCR- based diagnosis of tuberculosis have been developed.