in vivo-jetRNA^®+ is a lipid-based transfection reagent composed of preformed liposomes specifically developed for in vivo mRNA delivery. This reagent can be used to target unique or multiple organs, by using local or systemic injection routes, in various animal models (mice, rat, etc.). mRNA delivery using in vivo-jetRNA^®+ is user-friendly, with a simple 2-step protocol and can be used for vaccination purposes, oncology studies, genome editing (e.g., CRISPR/Cas9 technology) or protein replacement. It is also a reliable and convenient positive control for the development of Lipid nanoparticles (LNPs).