A dramatic overhaul of the population-based cancer registration system in Aichi Prefecture, Japan - Aichi Cancer Registry (ACR) - was undertaken in 1998, with a view to rationalization and strengthening of its effectiveness, supported by a grant from the Ministry of Health and Welfare. A more comprehensive organization encompassing the prefectural cancer center and prefectural public health centers (PPHCs), promoting PPHC-based primary and secondary cancer prevention has now been in operation since January 1999. Application of its basic components is also feasible for other population-based cancer registries in Japan, which share similar operation characteristics. This paper introduces the new cancer registration system in Aichi Prefecture, Japan.