The Interpersonal Stressor Scale (ISS) was developed based on Takahashi and Matsui (2009), and its reliability and validity were examined. In Study 1, analysis of data from 204 undergraduates indicated that the scale consisted of 4 subscales: incur-rejection, incur-aggression, aggression, and rejection. The scale had sufficient internal consistency (α=.75∼.85). In Study 2, 200 undergraduates completed the newly developed ISS, and the data analyses showed sufficient construct validity of the scale.