Background: The decade long California Tobacco Control Program is unique to the nation in its duration, emphasis, and level of funding. Programme emphasis is on changing social norms about smoking as a means to discourage smoking and thus reduce the harmful health effects of tobacco to the population. Methods: Data from the 1992 - 93, 1995 - 96, and 1998 - 99 Tobacco Use Supplements to the national Current Population Survey (n> 175 000 each period) were used to examine changes in norms regarding where smoking should "not be allowed at all'' in both California and in the rest of the USA. Venues queried were restaurants, hospitals, work areas, bars, indoor sports venues, and indoor shopping malls. Results: There were substantial increases in the percentages of the adult population (18+ years) stating that smoking should not be allowed in the venues queried in California by 1998 - 99 compared to 1992 - 93; only modest increases were observed in the rest of the USA. In fact, for most venues, the percentages for the rest of the USA were lower in 1998 - 99 than in California in 1992 - 93. Further, the percentage increase over this period in respondents stating that smoking should not be allowed in four or more of the six venues was 30% in California and 23% in the rest of the USA. The most dramatic percentage increase in California occurred among current smokers (93%). Conclusions: A strong, comprehensive tobacco control programme such as California's can influence population norms, including those of smokers, with respect to where smoking should not be allowed.