The baculovirus expression vector system (BEVS), first described in the 1980s, has proven successful for the production of many recombinant proteins. In principle, any foreign gene may be expressed in the BEVS for producing proteins in insect cells (IC). Protein therapeutics such as enzymes, tissue plasminogen activator (tPA), and viral and parasitic proteins have been produced using the BEVS-IC. Some viral structural proteins have been proven to self-assemble into ordered structures such as virus-like particles (VLP) during production in BEVS. These virus-like particles are commonly remarkably immunogenic and therefore potentially useful as vaccines. The baculovirus expression system is also promising for delivering genes into mammalian cells for gene therapy and other diverse applications.