The Rome IV Diagnostic Questionnaire for Functional Gastrointestinal Disorders in Adults (R4DQ) translates the Rome IV diagnostic criteria into questions that can be understood and reported by patients and research subjects. The intended uses of the R4DQ are (1) to provide inclusion criteria for clinical research studies, (2) to serve as case definitions for epidemiological surveys, and (3) to assist clinicians in arriving at a provisional diagnosis. Diagnostic questionnaires were also developed for pediatric FGIDs.