The development of cellular immune responses in primary human immunodeficiency virus type-1 (HIV-1) infection is accompanied by a dramatic decrease in plasma viremia and resolution of the acute clinical syndrome. The full nature of the immunological response and its consequences on HIV pathogenesis is still largely a mystery, but significant progress has been achieved in the characterization of some of the players involved. Several studies indicate that noncytolytic HIV suppression by CD8+ T lymphocytes may be inversely associated with viral load suggesting that this antiviral activity is important in host control of HIV replication. This review focuses on this antiviral activity by CD8+ T lymphocytes, which is distinct from that activity elicited by some cytolytic CD8+ T lymphocytes (CTLs).