In the United States, TB has re-emerged as a serious public health problem. In addition to those with active TB, an estimated 10 to 15 million people in the United States are infected with M. tuberculosis without displaying symptoms (latent TB) and about one in ten of these individuals will develop active TB at some time in their lives. Minorities are affected disproportionately by TB: 54 percent of active TB cases in 1999 were among African-American and Hispanic people, with an additional 20 percent found in Asians. This issue updates the reader on the diagnosis and treatment of tuberculosis.