The purpose of this article is to examine the extent to which trust directly affects public support for biotechnology, particularly in applications to food production and genetic modification of crop plants. Unlike previous research in which trust is assumed to be exogenous, this article posits that trust is endogenously determined. An econometric model is developed that controls for the endogeneiy of trust using instrumental variable and selection correction techniques. Using data from the U.S. Biotechnology Study, this study finds that the effect of trust on public support is substantially stronger than previous estimates.