A major advantage of recombinant DNA technology is its flexibility allowing for "on demand" production of specific proteins with theurapeutic value in heterologous expression systems. Gene expression vectors based on baculovirus, insect virus attacking mostly lepidopteran species, are frequently used for relatively inexpensive and fast production of such proteins. This expression system is recognized as one of the most powerful technologies for commercial synthesis of glycoproteins originating from vertebrate themselves or from vertebrate viruses. Glycosylation pathways utilized by insects are not identical, though they are similar to vertebrate glycosylation pathways. In the review special attention is given to the development of new virus-like particles (VLPs) potential vaccines which represent a novel class of subunit vaccines that are able to stimulate efficiently cellular and humoral immune responses against viral agents. Apart from production of vertebrate proteins or VLPs "on demand " in insect cells, a new exciting field of using baculovirus as gene delivery system to vertebrate cells was recently open which has a great potential for future uses of baculovirus as effective gene therapy vector.