Few scholars doubt the importance of trust in explaining variation in public perception of technological risk.  Relatively little, however, is known about the particular types of judgments that people use in granting or withholding trust.  This article presents findings from an empirical study that explores several dimensions of trust relevant for citizens' judgments of scientists involved in the development of GM food.  The relationship between particular dimensions of trust and perceptions of GM food risk is also explored, using structural equation modeling.  Results suggest that trust judgments based on the perception of shared values are most important in relation to GM food risk, but that judgments about scientists' technical competence are also important.