This article advances on existing studies in agenda-building theory, examining how a prominent sports magazine can build an agenda for mainstream press coverage, which in turn assists in building policy agendas. When Ken Caminiti, a former Most Valuable Player in the National League, admitted to Sports Illustrated in June 2002 that he used anabolic steroids during his award-winning season, mainstream newspaper journalists reported the revelations heavily, with many calling for changes in policy and the introduction of drug testing. As discussed here, policy-makers apparently listened: approximately three months after the magazine exposé appeared, baseball instituted a drug testing procedure. The study reveals how mainstream newspaper reports (n = 231) built on the Sports Illustrated investigation and how policy-makers reacted to a widespread condemnation of professional baseball, namely its apparent inability to police itself.