Inferences of others' social traits from their faces can influence how we think and behave towards them, but little is known about how perceptions of people's traits may affect downstream cognitions, such as memory. Here we explored the relationship between targets' perceived social traits and how well they were remembered following a single brief perception, focusing primarily on inferences of trustworthiness. In Study 1, participants encoded high-consensus trustworthy and untrustworthy faces, showing significantly better memory for the latter group. Study 2 compared memory for faces rated high and low on a series of traits (dominance, facial maturity, likeability, and trustworthiness), and found that untrustworthy and unlikeable faces were remembered best, with no differences for the other traits. Finally, Study 3 compared information about trustworthiness from facial appearance and from behavioral descriptions. Untrustworthy targets were remembered better than trustworthy targets both from behavior and faces, though the effects were significantly stronger for the latter. Faces perceived as untrustworthy therefore appear to be remembered better than faces perceived as trustworthy. Consistent with ecological theories of perception, cues to trustworthiness from facial appearance may thus guide who is remembered and who is forgotten at first impression. (Contains 2 tables and 3 figures.)