Human immunodeficiency virus (HIV) serology was performed in non-Asian-born patients 18-65 years old with newly diagnosed tuberculosis at a county tuberculosis clinic, and demographic and clinical features of HIV-seropositive and HIV-seronegative patients were compared. Sixty of 128 eligible patients agreed to participate, of whom 17 (28%) were seropositive. Risk of HIV was associated with homosexual contact, intravenous drug use, or both; however, 4 (24%) of the 17 seropositives denied risk behaviors. Significantly more blacks (48%) than whites (10%) or Latinos (20%) were HIV-seropositive (P less than .01). Site of disease, tuberculin reactivity, response to therapy, drug toxicity, and relapse did not differ significantly between groups. HIV-seropositive patients had significantly lower median CD4+ cell counts (326/mm3, range 23-742/mm3, vs. 929/mm3, range 145-2962/mm3, P less than .0005) and median CD4+:CD8+ ratios (0.50, range 0.14-1.07 vs. 1.54, range 0.35-4.36, P less than .0001). HIV infection is associated with clinically typical tuberculosis and HIV screening of tuberculosis patients is recommended in areas where HIV is endemic.