Government action and the advocacy activities that influence it are as important a concern for cancer control as they are for any other public issue. Policy advocacy strategies have proven themselves effective in cancer prevention efforts involving tobacco use and nutrition. Much of what has been learned from this experience can be applied with great effect in advocacy efforts for other cancer control measures. The implementation of Proposition 99, the 1988 tobacco tax initiative in California, illustrates the effectiveness of aggressive policy advocacy strategies such as provocative paid advertising, mobilization through coalitions, and community-level public relations, to bring about government action at all levels of government and in the private sector. Today, largely as a result of these activities, more than 70 of California's 471 cities have a 100% smokefree workplace and/or a 100% smokefree restaurant ordinance, and nearly 300 cities currently have ordinances that restrict smoking pollution and/or restrict youth access to cigarette vending machines. About 150 cities have ordinances that were either adopted or greatly strengthened since 1990 when the program hit the streets. Ironically, although the primary aim of these strategies has been to reduce uptake of tobacco use by adolescents, the program's gains so far--including the reduction in adult smoking prevalence from 26% in 1988 to 20% in 1993, for an estimated savings in 1993 alone of $386 million in direct medical costs in the state--have been the result of adult smokers quitting, especially those older than 50.