Agenda setting is regarded as a key process in policymaking. This study first examines the trends in newspaper articles on smoking and health and the debates on the issue in the Diet in Japan for the period 1945-1990. Then relationships of those articles and debates with national administrative actions are analyzed. Although the media helped set the agenda in the Diet before the emergence of the nonsmokers' rights movement, it did not do so thereafter. On the other hand, media reports continued to be associated with various aspects of administrative policy making throughout the study period and played an important role in mobilizing administrative agencies. Effects of mass media on agencies were regarded as largely independent of the debates in the Diet. It is also noted that simple "scientific" reports on the health hazards of smoking had no association either with agency action or with Diet debates. This indicates that issue building, which consists of creating a package of ideas about the facts, the causal theories, the responsibilities, and the feasible solutions, is important when scientific facts are to be dealt with by policymakers.