The ability of lentiviral vectors to transduce and stably integrate their genomes into non-dividing cells was the major reason for the development of the HIV-1 based vector gene delivery system. The first VSV-G pseudotyped lentiviral vectors fulfilled these expectations by ferrying large genetic payloads to non-dividing cells in vitro and in vivo. Here we discuss advances in HIV-1 vector systems which lead to improvement in biosafety, transduction efficiency, longevity and regulation of transgene expression, and vector production. The successful use of the advanced HIV-1 based vector system opened new avenues in establishing transgenic animal models for basic research. Additionally, we describe accomplishments using HIV-1 based vectors to correct pathological courses of incurable diseases in preclinical animal models including Parkinson's disease and beta-thalassemia.