We describe the development of the Undergraduate Stress Questionnaire (USQ), a life events checklist designed to measure stress among undergraduates. Several studies demonstrate the USQ's validity. The USQ correlates positively with physical symptoms and negatively with mood. Students rated the USQ as the most complete and accurate of four different life events questionnaires. In a panel study, the USQ closely tracked subjective reports of stress, both during the term and finals week. The USQ predicted symptoms more reliably than three other stress measures, controlling for negative affect. Students waiting in the college infirmary score higher on the USQ than students socializing on campus. Finally, we compare the checklist format to subjective scaling, and show the superiority of the checklist version. We discuss the usefulness of the USQ in terms of validity, representativeness, adaptability, brevity, and low confounding with negative affect.