The absence of effective treatments makes AIDS one obvious candidate among the infectious diseases which might be treated by somatic gene therapy. Since HIV1 predominantly infects cells of the haematopoietic system, multipotent stem cells or more mature CD4+ cells constitute potential targets for the introduction of a foreign antiviral gene that will inhibit HIV1 replication and/or spread. Reimplantation of the genetically-modified cells into HIV-infected patients should theoretically allow the repopulation of the host with HIV1-resistant CD4+ cells that might be able to control virus propagation in vivo. Alternatively, increased knowledge of the immunological mechanisms involved in the control of virus infection and propagation has led to the development of different strategies to augment host anti-HIV1 cytotoxic T lymphocyte responses in an effort to prevent virus spread and, hence, the onset of AIDS. While the therapeutic value of such approaches still remains unknown, these experimental treatments hold real promise that require thorough clinical evaluation.