Tuberculosis is an increasing problem around the world, including the United States. The human immunodeficiency virus epidemic has dramatically and adversely influenced the control of tuberculosis. Effective chemotherapy is available to prevent and treat disease. Recent public health guidelines support a 6-month regimen of isoniazid and rifampin for 4 months to treat uncomplicated tuberculosis. Patients who are human immunodeficiency virus- or acquired immunodeficiency syndrome-positive should be treated for longer periods, usually 9 months. Tuberculosis is a contagious disease. Increased risk of transmission occurs in certain settings such as health care facilities and correctional institutions. There may be racial differences in susceptibility to infection with tuberculosis, but close contact with an infectious case is the chief risk factor. New technologies promise the possibility of 1− or 2-day diagnosis. Two- or 3-month preventative therapy for tuberculosis may be possible using rifampin and pyrazinamide based upon results in a laboratory animal model.