The importance of genetic resource preservation has been highlighted in the literature as a means of maintaining genetic diversity. Among the various methods of preserving such resources, semen cryopreservation can be advantageous because it reduces the time of restoring genetic resources and is less technique-dependent. The Korean Oge (KO) chicken is a Natural Monument and is recognized as an important genetic resource in Korea. However, successful cryopreservation methods for KO chickens have yet to be reported. Therefore, we completed cryopreservation methods in KO chickens using N-methylacetamide (MA) as a cryoprotectant. Also we performed additional experiments to identify whether fertility and hatchability are affected by long-term storage. Finally, we examined sperm viability in the cryopreserved semen. Our results suggest that the cryopreservation method using MA can be applied to KO chickens regardless of storage period and could be a useful tool for the preservation the endangered avian species.