Using Fishbein's multiattribute and mediation models as conceptual frameworks, we propose that the impact of trust, awareness, sense of outrage, and socio-demographic variables on attitudes toward agrobiotechnology are mediated by risk perceptions. The proposition was validated using large survey data collected in the United States and United Kingdom. Results show that trust, sense of outrage, and socio-demographic factors play an important role in shaping public attitudes about agrobitoechnology, largely via their links to risk perceptions. Moreover, risk perceptions exert a greater effect on public attitudes toward agrobiotechnology than benefit perceptions. Finally, the attitudes of U.K. consumers were more susceptible to negative attributes when compared with U.S. consumers. Copyright 2004, Oxford University Press.