The news media are a primary source of cancer prevention and detection information for the general public, but little is known about the content of cancer prevention and detection messages in mainstream media. This study examines how cancer prevention and screening efficacy messages are presented in cancer news media coverage. Efficacy messages provide information about skills related to prevention and screening behaviors. Analysis of cancer-related stories in 44 major US daily newspapers during 2003 (n=2448) reveals that efficacy messages were rarely present in cancer stories. Efficacy messages were less likely to appear in stories that had a ‘local’ angle, but efficacy messages were more likely to appear in stories that contained ‘mobilizing information’ (additional resources for readers) or stories that mentioned highly preventable cancers (lung, skin, esophagus and bladder). The discussion includes a theory of norms for effectively influencing cancer-related behaviors through news reports. Implications of this work extend to the lack of efficacy messages when highly detectable cancers are mentioned, thus the lack of actionable information when health risks are presented, and a dearth of efficacy messages when localized information is present, each of which represent key areas for encouraging health journalists to include more efficacy statements.