The epidemiology of tuberculosis is changing in the United States as a result of immigration, yet the extent to which different classes of immigrants contribute to overall morbidity is unknown. Tuberculosis in nonimmigrant visitors is of particular interest as they are currently exempt from screening requirements. We conducted a prospective survey of all culture-positive tuberculosis patients in Tarrant County, Texas from 1/98 to 12/00. Immigration status of foreign-born patients was classified as permanent residents, undocumented, or nonimmigrant visitors. Of 274 eligible participants, 114 (42%) were foreign-born; of these, 67 (59%) were permanent residents, 28 (25%) were undocumented, and 19 (17%) were nonimmigrant visitors. Among the foreign-born, we observed significant differences by immigration status in multidrug resistance (p = 0.02), human immunodeficiency virus (HIV) infection (p = 0.0007), and hospitalization (p = 0.03 for ever/never, 0.01 for duration). Compared with other immigrants, more nonimmigrant visitors were multi-drug-resistant (16 % versus 11% of undocumented residents and 1% of permanent residents), were HIV-positive (32% versus 0% of undocumented and 5% of permanent residents), were hospitalized (47% versus 36% of undocumented and 19% of permanent residents), and had lengthy hospitalizations (median [midspread] days = 87 [25 to 153] versus 8.5 [4 to 28] for undocumented and 10 [7 to 24 d] for permanent residents). We found nonimmigrant visitors to be an important source of tuberculosis morbidity in Tarrant County. Further studies in other regions of the U.S. are needed to determine if screening and treatment recommendations of persons who spend extended periods in the U.S. should be raised to the standards set for permanent residents.