To determine the risk of active tuberculosis associated with HIV infection, we retrospectively studied a cohort of HIV-seropositive and HIV-seronegative women participating in an HIV perinatal transmission study in Kinshasa, Zaire. After a median follow-up of 32 months, new cases of proven pulmonary or clinically diagnosed tuberculosis occurred in 19 of the 249 HIV-seropositive women (7.6%, 3.1 cases per 100 person-years) compared with 1 of the 310 HIV-seronegative women (0.3%, 0.12 cases per 100 person-years), for a relative risk of 26 (95% confidence interval, 5 to 125). Proven pulmonary tuberculosis was diagnosed in 7 HIV-seropositive women (2.8%, 1.2 cases per 100 person-years) and 1 HIV-seronegative woman (0.3%, 0.12 cases per 100 person-years), for a relative risk of 10 (95% confidence interval, 1.5 to 47). We estimated that 66 cases of proven pulmonary tuberculosis in 100,000 person-years of follow-up in women of childbearing age could be attributed to HIV; this is 35% of their estimated total incidence of proven pulmonary tuberculosis. Among those followed for 2 yr, 27 (11%) of 243 HIV-seropositive women died during 2 yr of follow-up compared with none of 296 HIV-seronegative women (p < 0.001). In HIV-seropositive women with proven or clinically diagnosed tuberculosis mortality was even higher: 5 (26%) of the 19 HIV-seropositive women with proven pulmonary or clinically diagnosed tuberculosis died during follow-up compared with 22 (10%) of the 224 HIV-seropositive women not diagnosed as having tuberculosis (relative risk 2.7; 95% confidence interval, 1.1 to 6.3). This cohort study quantifies the sizable contribution of the HIV/AIDS epidemic to increasing tuberculosis morbidity and mortality in a central African City.