The Korean National Codes Against Cancer provide guidelines for cancer prevention. The inaugural edition was published in 2006, followed by a major revision in 2016. This study aimed to describe the historical context, scientific rationale, and revision process of these guidelines. With rising cancer incidence in the early 2000s, the Korean government recognized the need for national cancer prevention guidelines, prompting the National Cancer Center to initiate their formulation. The Division of Cancer Prevention reviewed global literature on cancer trends and Korea-specific studies on cancer risk factors. The final set of 10 recommendations comprising the Korean National Codes Against Cancer was approved by the National Cancer Control Committee after achieving expert consensus on cancer prevention. The finalized guidelines are firmly grounded in scientific evidence. The 10 current recommendations include: (1) no smoking and avoidance of secondhand smoke; (2) consuming sufficient fruits and vegetables as part of a balanced diet; (3) reducing salt intake and avoiding burnt or charred foods; (4) limiting alcohol consumption; (5) engaging in regular physical activity (at least 30 minutes a day, 5 days a week); (6) maintaining a healthy body weight; (7) receiving immunization against hepatitis B virus and human papillomavirus; (8) practicing safe sex by maintaining a single sexual partner and using condoms; (9) following health and safety guidelines to avoid exposure to occupational carcinogens; and (10) undergoing regular cancer screening. This study detailed the sources and procedures involved in formulating and revising the Korean National Codes Against Cancer.