Abstract (Resource) The Rat Resource and Research Center (RRRC) provides a unique and essential repository service to the research community by importing, storing and distributing a large number of rat strains and embryonic stem cell lines. It assures that valuable models are preserved and made available to interested investigators, allows researchers to satisfy NIH requirements for resource sharing, relieves individual investigators from the burden of animal distribution and ensures that models are maintained with rigorous genetic quality control and health monitoring standards to enhance experimental reproducibility. Our objective during the next funding period is to continue to improve and expand the functions and capabilities of the RRRC to provide biomedical investigators with the rat models, embryonic stem cells, related reagents, protocols and services that will facilitate their research. We will accomplish this by developing new and utilizing existing technologies to improve the quality of the resource’s acquisition, cryopreservation, storage, quality control, and distribution of rats, sperm, embryos and embryonic stem cells. We will continue to evaluate and improve our service delivery and our communication with the biomedical research community. We will expand our services which already include re-derivation, colony management, a wide array of genetic analysis options, model creation using CRISPR/Cas9 technology, and microbiota characterization on a fee-for-service basis. In this way, the RRRC will strengthen its ability to serve as a much-needed “one stop” resource for investigators using rats in biomedical research.