Background: Cancer incidence and mortality continues to rise worldwide including in Kenya. Among the groups that are likely to get cancer in future are Kenyan youth that engage in behavior that can increase their lifetime cancer risk. Despite this awareness, little is known about Kenyan youth's understanding of cancer, cancer risk, and cancer prevention. Such awareness is needed to inform germane cancer prevention and health promotion initiatives. Aim: The purpose of this ethnographic study was to explore Kenyan youth's understanding of cancer, cancer risk, and cancer prevention. Methods: Fifty-three youth (ages 12-19) took part in individual interviews and focus group discussions. Results: In their conceptualization of cancer, youth described cancer in ways that are grouped into two themes: there is no other disease like it and lay understanding through metaphors. In their conceptualization of cancer risk, youth described cancer in ways that are grouped as cancer risk as lifestyle factors and the process of risk perception. Finally, in conceptualization of cancer prevention, youth described cancer prevention in ways that are grouped into the following themes: avoiding cancer risk factors, avoiding peers who partake in risk factors, and being healthy. Conclusion: This study is the first of its kind to be conducted in Kenya and adds to the body of knowledge in this area. Despite limited cancer control plans, youth described the grim consequences of getting cancer, their chances of getting the disease, and proposed opportunities for prevention. The study results will create a platform for future cancer prevention research and health promotion programs in Kenya and other part of Africa.