Tuberculosis (TB) and human immunodeficiency virus (HIV) infections are the deadliest chronic infections globally. Although each is deadly alone, they are deadlier together, with TB causing one-quarter of AIDS-related deaths and HIV infecting at least 15% of patients with TB worldwide. Historically, the 2 diseases were treated through specific, vertical programs. Strong activism and massive scientific investment have boosted the global response to AIDS, whereas TB has suffered from weak advocacy and anemic research funding. However, since 2004, there has been increasing collaboration and convergence between programs to control the 2 diseases, driven by the recognition that program cooperation leads to synergistic gains in strengthening responses to the 2 diseases and to health systems in general. Progress to date is incomplete, however, and countries must rededicate themselves to scaling up prevention and treatment programs for TB and HIV infection toward universal access, while pursuing accelerated research efforts to develop effective vaccines, better treatments, and cures for both diseases.