The human immunodeficiency virus (HIV) epidemic has led to an increase in the incidence of tuberculosis globally, particularly in sub-Saharan Africa. Coinfection with HIV leads to difficulties in both the diagnosis and treatment of tuberculosis. Because of the poor performance of sputum smear microscopy in HIV-infected patients, more sensitive tests-such as liquid culture systems, nucleic acid amplification assays, and detection of mycobacterial products in various body fluids-are being investigated. The treatment of coinfected patients requires antituberculosis and antiretroviral drugs to be administered concomitantly; challenges include pill burden and patient compliance, drug interactions, overlapping toxic effects, and immune reconstitution syndrome. Both multidrug-resistant and extensively drug-resistant tuberculosis can spread rapidly among an immunocompromised population, with resulting high mortality rates. Current guidelines recommend starting antiretroviral treatment within a few weeks of antituberculosis therapy for patients with CD4 cell counts <350 cells/microL; however, important questions about the drug regimens and timing of antiretroviral therapy remain. Ongoing trials may answer many of these unresolved questions.