The human immunodeficiency virus type-1 virions are composed both of virus-encoded and host cell proteins incorporated at the time of budding.  Membrane associated proteins as well as cytosolic host-cell components are known to be associated to HIV-1 virions.  Such virus-associated host-cell proteins have been proposed to be either present at the site of budding and packaged into HIV virions by a passive phenomenon, or directed to viral budding structure by the mean of direct interactions with HIV proteins or nucleic acids.  Non random inclusion of host molecules into viruses lead to speculate that such cellular compounds may participate to HIV life cycle in an active way and therefore act as factors contributing to the development of immunological disorders observed in AIDS.  Here, we review the nature of virus-associated host cell proteins and the potential functional role played in the biological properties of the virus.  The overview of mechanisms regulating relations of HIV and host cell components will allow a better understanding of their consequences on HIV-1 pathogenesis.