The pseudovirions are virus-like particles generated by in vitro production of HIV-1 viral proteins which are capable of assembly into particles. The presence of gag gene products in addition to envelope glycoprotein should assist in humoral and cellular immunologic responses to internal HIV-1 viral proteins. The pseudovirion vaccine has been tested in preclinical trials in mice, guinea pigs, rabbits, and nonhuman primates with good safety and immunogenicity profile.