Both Japan and Korea provide population-based screening programs. However, screening rates are muchhigher in Korea than in Japan. To clarify the possible factors explaining the differences between these twocountries, we analyzed the current status of the cancer screening and background healthcare systems. Populationbasedcancer screening in Korea is coordinated well with social health insurance under a unified insurer system.In Japan, there are over 3,000 insurers and coordinating a comprehensive strategy for cancer screening promotionhas been very difficult. The public healthcare system also has influence over cancer screening. In Korea, publichealthcare does not cover a wide range of services. Almost free cancer screening and subsidization for medicalcost for cancers detected in population-screening provides high incentive to participation. In Japan, on theother hand, a larger coverage of medical services, low co-payment, and a lenient medical audit enables peopleto have cancer screening under public health insurance as well as the broad range of cancer screening. Theimplementation of evidence-based cancer screening programs may be largely dependent on the backgroundhealthcare system. It is important to understand the impacts of each healthcare system as a whole and to matchthe characteristics of a particular health system when designing an efficient cancer screening system.