Lentiviral vectors become more and more famous for the use as gene vector for gene therapy purposes for the treatment of acquired or inherited diseases. In this review, the present state of the art of the production of lentiviral vectors is presented with particular emphasis on the large scale production of these vectors for preclinical and clinical purposes. In contrast to oncoretroviral vectors which are produced using stable producer cell lines, clinical grade lentiviral vectors are essentially produced by transient transfection of 293 or 293T cells grown in Cell Factories. The main reason is that these production processes have been developed when good and safe LV producer cell lines were not available. With respect to the purification of lentiviral and in agreement with actual developments in the biotech industry, rather sophisticated downstream processing protocols have been established in order to remove any potentially dangerous process derived contaminant, such as plasmid or host cell DNA or host cell proteins. This review presents large scale production means for LV vectors, the different downstream processing steps as used for the purification of LV vectors as well as LV specific safety issues. Published large scale production and purification processes of lentiviral vectors and their process performances are compared.