Infectious variants of human immunodeficiency virus (HIV) can be isolated from peripheral blood mononuclear cells (PBMC) of infected individuals by propagating the virus in co-cultures with healthy donor PBMC. Standardized culture protocols have been designed specifically for the isolation of HIV type 1 (HIV-1) and proven effective for the isolation of virus from virtually all HIV-1-infected individuals. For the isolation of HIV-2, however, standard HIV-1 culture protocols have been only partially effective. While suitable for the isolation of HIV-2 from PBMC of individuals in advanced stages of disease, they appeared largely inadequate for the isolation of HIV-2 from asymptomatically HIV-2-infected individuals. This chapter describes a variant HIV isolation procedure with culture conditions adapted to the isolation of HIV-2 from PBMC of "healthy" HIV-2-infected individuals, i.e., individuals with high CD4+ T-cell numbers and no detectable viral RNA in plasma. By using a limiting dilution format, several biological clones representing individual HIV variants can be obtained from the PBMC of an infected individual. In addition, the frequency of PBMC infected with HIV-2 variants capable of propagating in vitro can be estimated.