Mycobacterium tuberculosis is one of the most ubiquitous pathogens in the world: estimates are that roughly one third of the world’s population is infected with the bacillus and it is responsible for 8 to 12 million cases of active TB each year and 3 million deaths. The global resurgence of TB has made it imperative that improved vaccines, diagnostics and drugs be devised to control the current epidemic, which needs the proper understanding of the disease pathogenesis and the host immune response against TB.The complement system is an important part of the host immune system. Complement components and their activated fragments generally serve to amplify the effects of the interaction of antigen with antibody. There is paucity of information regarding the role played by the complement system in pulmonary tuberculosis. This work is aimed to know the status of the complement system in pulmonary tuberculosis.