In evaluating complex new technologies, people are usually dependent on information provided by others, for example, experts or journalists, and have to determine whether theycan trust these information sources. This article focuses on similarity as the basis for trust.The first experiment (N = 261) confirmed that a journalist writing about genetically modified (GM) food was trusted more when his attitude was congruent with that of his readers. In addition, the experiment showed that this effect was mediated by the perceived similarity of thejournalist. The second experiment (N = 172) revealed that trust in a journalist writing aboutthe focal domain of GM food was even influenced by him expressing a congruent attitudein an unrelated domain. This result supports a general similarity account of the congruenceeffect on trust, as opposed to a confirmatory bias account. © 2009 Society for Risk Analysis.