This study tested the central rational-emotive hypothesis that greater "inappropriate" emotional distress is caused by irrational rather than rational beliefs about undesirable situations. Ellis and Harper (1975) have suggested that "inappropriate" emotions (such as anger) differ qualitatively from "appropriate" emotions (such as annoyance). Previous research, however, indicates that irrational beliefs are associated with greater "appropriate" as well as "inappropriate" negative emotions. In this study, a 3 ×2 pretest-posttest factorial design was used, in which 10 undergraduates of either sex were randomly assigned to one of three treatments, which involved imagining being in a situation. The control condition comprised an emotionally neutral scene, while the two experimental treatments contained rational and irrational statements about being left alone by one's partner at a party. The experimental manipulation was successful, and both "inappropriate" and "appropriate" negative emotions were found to be greater in the irrational condition as compared to the neutral or rational condition. Thus irrational beliefs were shown to have an effect on emotions, but the emotions associated with irrational beliefs differed from those associated with rational beliefs in quantity rather than in quality. © 1991 Plenum Publishing Corporation.