Knockout Brown Norway (BN) rat could be a useful disease model for human disorders,however,a failure to derive embryonic stem (ES) cells disturbs the further development of the model.In this study,we reported a case of successful derivation of the BN rat ES cells with the derivation efficiency comparable to that of Sprague Dawley (SD) rats.The BN rat ES cells expressed the key transcription factors,and were able to form embryonic bodies (EBs) when being differentiated in vitro.After injecting the BN rat ES cells into the SD rat blastocysts,high-contribution chimeric rats were generated and could survive to their adulthood.Our success in generating pluripotent rat ES cells will benefit the generation of the knockout rats in the future.