Background. Interpersonal stress generation is an important maintaining factor in major depression; however, little is known about the psychological mechanisms that undermine interpersonal functioning. This study investigated the role of deficits in person perception to this regard. Method. Depressed patients (n = 20) and healthy controls (n = 20) completed a false recognition task that measured participants' tendencies to make spontaneous trait inferences (STIs), that is to spontaneously ascribe personality traits to other people. Participants then reported interpersonal daily hassles for one week following the task. Results. Tendencies to make STIs were significantly higher in depressed patients, particularly those with a history of childhood trauma. The degree to which participants made STIs was significantly related to depression severity, and predicted the occurrence of interpersonal daily hassles during follow-up across, but not within groups. Conclusions. The results suggest that depressed patients show characteristic biases in person perception that may contribute to the generation of interpersonal stress.