Tuberculosis remains one of the biggest killers of the human race, with approximately 8 million cases and 2 million deaths each year. It is closely associated with HIV/AIDS and is one of the commonest comorbidities of AIDS. The diagnosis is made on the basis of symptoms, usually cough, malaise, weight loss, and night sweats, confirmed by bacteriological testing for smear and culture to identify the causative organism: the Mycobacterium tuberculosis complex. Though the lung is the most commonly affected organ, tuberculosis can cause disease of virtually any part of the body. Disease of the meninges, bones and joints, and abdomen are particularly problematic. Treatment is with at least four drugs initially: isoniazid, rifampicin, pyrazinamide, and ethambutol. This may be reduced to the first two after 2 months and if the bacterium is fully sensitive. Drug-resistant tuberculosis is an increasing problem and new drugs are desperately required. BCG remains the only but fairly weak vaccine available. New research into vaccines is ongoing. The new interferon release-based blood tests for tuberculosis infection may eventually replace the 100-year-old tuberculin skin test.