The present study tested the reliability of a self-report diagnostic measure of generalized anxiety disorder (GAD) based on DSM criteria. Among two samples of undergraduate students, 47-80% of the GAD diagnoses by questionnaire were confirmed by diagnostic interview, with the higher rate being associated with DSM-IV criteria. Categorization of a participant as Non-GAD by questionnaire was found to be 100% reliable by interview. Given these findings as well as prior empirical support for the validity of the measure, this questionnaire has utility for identifying analogue GAD and Non-GAD participants from undergraduate populations for use in preliminary investigations of the mechanisms and functions associated with chronic worry and GAD.