Background: After Genome project, cancer genetic information is being rapidly changing. Everyday nurses are incorporating current cancer genetic knowledge and genetic testing into their practice. So their cancer genetic knowledge is important for ensuring quality of cancer patient care and education. Purpose: This study is performed for describing the Korean nurses’’ current knowledge level about the hereditary breast cancer. Method: This national wide survey used 15-item questionnaire which is modified from the Breast Cancer Genetic Counseling Knowledge Questionnaire originally developed by Erblich et al.(2005). Three hundred and nine nurses were recruited for this survey from April 1, 2006 to September 30, 2006. Result: Nurses’’ knowledge level about the hereditary breast cancer was not high. Clinical nurses with master degree, working large hospital located in Seoul had higher knowledge about hereditary breast cancer. Education related to cancer genetics was significantly impact on the level of nurses’’ knowledge. Conclusion: Cancer genetic educational program for Korean nurses is strongly needed for delivering cancer care services sensitive to ever-changing cancer genetic information.