HIV infection results in progressive and ultimately profound immune suppression in the absence of treatment; moreover, there is no evidence that the infection is ever eradicated by host defenses. However, the remarkable ability of some HIV infected persons to maintain viral loads below the limits of detection in the absence of antiretroviral therapy provides evidence that the immune system can achieve the upper hand in this infection. Since the discovery of HIV-specific CD8 T cells in 1987, numerous laboratories have contributed to a convincing array of data from patients indicating that these cells are the main contributors to controlling acute and chronic HIV infection. Massive induction of HIV-specific CD8 T cells occurs following onset of viremia in hyperacute infection, the rapidity and magnitude of which are associated with set point viral control. However, in most persons dysfunction and dysregulation of these responses as well as immune escape rapidly ensue. Emerging data provide insights to harnessing and maintaining the antiviral efficacy of CD8 T cells , which will be key to key to functional and sterilizing cure strategies.