In the world of transgenesis, for a decade, a technological revolution has taken place with the emergence of several genome editing technologies. It is now possible to introduce various genetic modifications, not only in mice (where the use of embryonic stem cells has been widespread since years) but in a wide range of species. Animal models are useful tools for the study of human diseases and to test and validate potential therapies. The CRISPR-Cas9 technology, introduced in 2012, has developed very fast due to its ease of use, its efficiency and its moderate cost. It has allowed the democratization of gene editing in a large number of species. These tools work as highly accurate molecular scissors and generate a double-strand break of the DNA at the targeted sequence. This breakage leads to the activation of repair pathways that facilitate the introduction of genomic modifications (Knockout, knock-in). On the Transgenesis Rat ImmunoPhenomics (TRIP) platform in Nantes, we generate genetically modified rats using these new tools by microinjection or electroporation in the unicellular embryo. We characterize the genetic modification. Once the lineage is established, the phenotype can be analyzed by the appropriate histology techniques. Among our projects, we have generated rat models for Duchenne muscular dystrophy, cystic fibrosis and immunodeficiency. These new genome editing tools allow precise but various genetic modifications, offering to the scientific community immense possibilities for the study of new models.