Of the 24 inmates who had positive cultures, 19 (79%) had tuberculosis with genes whose DNA matched that from other infected inmates. The 2 guards with positive cultures had tuberculosis with DNA tests that matched the most common form in the inmates. Inmates with tuberculosis had been incarcerated about 15 times on average. Since 1995, 43% of persons in Memphis with newly discovered tuberculosis had been inmates in this jail at some time.