Objectives: To assess parental influence on smoking behaviour by high school students in an Asian culture and to compare the relative importance of parental and peer influence. Methods: A 5% nationally representative sample, including 44 976 high school students in 10th to 12th grade (aged 15-18 years) in Taiwan, were surveyed in 1995. Each completed a long self administered questionnaire. Parental influence was measured by examining both parental behaviour ( smoking status) and attitudes (perceived "tender loving care" (TLC) by adolescents). Changes in smoking status were used to determine peer influence, defined as the increase in the likelihood of smoking from grade 10 to 12 in a steady state environment. Odds ratios (ORs) were calculated for parental and peer influence, using logistic regression. Results: Adolescents of smoking parents with low TLC had the highest smoking rates and those of nonsmoking parents with high TLC had the lowest. The difference was more than twofold in boys and more than fourfold in girls. When either parental smoking status or TLC alone was considered, parental influence was similar to peer influence in boys, but larger than peer influence in girls. However, when smoking status and TLC were considered jointly, it became larger than peer influence for both groups ( OR 2.8 v 1.8 for boys and OR 3.9 v 1.3 for girls). Conclusion: When parental influence is taken as parental behaviour and attitude together, it plays a more important role than peer influence in smoking among high school students in Taiwan. This study, characterising such relationships among Asian populations for the first time, implies that future prevention programmes should direct more efforts toward the parental smoking and parent-child relationships, and not aim exclusively at adolescents in schools.