Lentiviral vectors have emerged over the last decade as powerful, reliable, and safe tools for stable gene transfer in a wide variety of mammalian cells. Unlike other vectors derived from oncoretroviruses, they allow for stable gene delivery into most nondividing primary cells, including neurons. This is why lentivectors (LVs) are becoming the most useful and promising tools in the field of neuroscience, not only for research, but also for future gene and cell therapy approaches. LVs derived from HIV‐1 have gradually evolved to display many desirable features aimed at increasing both their safety and their versatility. These latest designs are reviewed in this unit. This unit also describes protocols for production and titration of LVs that can be implemented in a research laboratory setting, with an emphasis on standardization to improve transposability of results between laboratories. Curr. Protoc. Neurosci. 53:4.21.1‐4.21.23. © 2010 by John Wiley & Sons, Inc.