This study investigated state anger and individual differences in negative reciprocity orientation as predictors of individuals’ willingness to cooperate with strangers. In order to observe real behavior, we used a trust game that was played over six periods. In the trust game a first player (sender) determines how much of a certain endowment she/he wants to share with a second player (trustee), who then can give something back. We varied whether participants received feedback (feedback [yes, no]) about the trustee’s behavioral decision (amount sent back). Supporting our hypotheses, the results suggest that feedback compared to no feedback about the trustee’s behavior increased anger. Specifically, information about low back transfers triggered anger and non-cooperation in return. Importantly, participants with a strong negative reciprocity orientation reported higher levels of anger and were less willing to cooperate with the trustee compared to those with low negative reciprocity orientation. Moreover, even when anger was low, individuals with a strong negative reciprocity orientation were less willing to cooperate compared to those with a low negative reciprocity orientation. Thus, negative reciprocity orientation seems to arouse a spiral of distrust. Theoretical and practical implications of these findings are discussed.