PURPOSE: This study was performed to evaluate Korean nurses' knowledge about hereditary colorectal cancer (HCRC). METHODS: A modified 15-item HCRC knowledge questionnaire was developed based on previous research. One hundred and forty-eight nurses have completed the questionnaire from February to April, 2011. RESULTS: The average score of nurses' knowledge was 11.25+/-1.54. Ninety-seven percent of nurses knew about colonoscopy check up schedule and family pedigree. However, only 20% of nurses knew about the rate of passing on mutation genes to offspring and risk of developing CRC among carriers. Only 13.5% of nurses had previous genetic education experiences. Working in oncology units, taking care of CRC patients, and participating in genetic education were not associated with nurses' HCRC knowledge. CONCLUSION: Various factors influence nurses' knowledge about HCRC. Repeated study with larger national sample of nurses is recommended to identify the factors affecting nurses' knowledge level in order to develop efficient genetic education programs for HCRC patients and their families by nurses.