Two studies examined the impact of trait and category diagnosticity on the social information processing of depressed and nondepressed participants. As suggested by the Weary, Marsh, Gleicher, and Edwards (1993) model of the effects of depression on social information processing, it was predicted that depressed participants would be especially sensitive to the diagnosticity of the available information when forming an impressions of another person. In Study 1, depressed participants were more sensitive than nondepressed participants to trait diagnosticity when forming an impression. In Study 2, depressed participants were more sensitive than nondepressed participants to both trait and category diagnosticity when forming an impression.