As part of its war on drugs, the U.S. government spent nearly $1 billion between 1998 and 2004 for the National Youth Anti-Drug Media Campaign. The campaign had three goals: educating children and teenagers (ages 9 to18) on how to reject illegal drugs, preventing them from starting drug use, and convincing occasional users to stop. Analyzing the effects of this campaign is important not only for future funding decisions but also for more effective targeting of future efforts. This Issue Brief summarizes a Congressionally-mandated evaluation of the campaign’s effects on youths’ cognitions and behavior around marijuana use.