The CRISPR-Cas9 system allows rapid generation of a large spectrum of genetically modified mouse models. Here we present efficient gene knock-out, knock-in and exon deletion projects undertaken at our transgenesis platform located in the near suburbs of Paris (SEAT-TAAM PHENOMIN). The delivery of different forms of spCas9 into the pronucleus of murine zygotes and the analysis of injected embryos at the blastocyst stage or beyond have allowed us to obtain mouse models from hybrid and inbred strains for studies in myology, immunology, reproduction biology, etc. with a success rate of about 10 % (KI)–70 % (KO) in the founder generation.