The forced opening of Taiwan's tobacco market in 1987 has changed the smoking environment. This study analyzes the effects this market opening had on Taiwan's secular smoking rates over 15 years. The data sources used were consumer surveys conducted by the Taiwan Tobacco & Wine Monopoly Bureau 1964-1996, the 2001 National Health Interview Survey, and a series of annual per capita gross national product (GNP) data reported by the Directorate-General of Budget, Accounting & Statistics. After Taiwan's tobacco market was forced open in 1987 by the U.S. government in trade negotiations, smoking rates rose (7%-10% for males and 39%-75% for females) for the first three years. After the initial 3-year surge, smoking rates gradually declined to 1986 baseline rates or even lower for all groups except females aged 30 and younger, who have shown a small but steady increase in cigarette consumption. Results of multiple regression analysis showed per capita GNP and age to be the two major factors affecting smoking rate change after the Taiwan market opening. National tobacco control policies and campaigns seem to have an impact on tempering the effect of foreign tobacco imports in all groups, except young females, whose rise in smoking rate is significant and alarming.