In conjunction with the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks public-private partnership with the U.S. Food and Drug Administration and the American Pain Society, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks-American Pain Society Pain Taxonomy (AAPT) initiative strove to develop the characteristics of a diagnostic system useful for clinical and research purposes across disciplines and types of chronic pain conditions. After the establishment of these characteristics, a working group of clinicians and clinical and basic scientists with expertise in abdominal, pelvic, and urogenital pain began generating core diagnostic criteria and defining the related extraintestinal somatic pain and other symptoms experienced by patients. Systematic diagnostic criteria for several common abdominal, pelvic, and urogenital pain conditions are in development. In this report, we present the proposed AAPT criteria for irritable bowel syndrome (IBS), the most common chronic, noncancer abdominal pain condition. A systematic review and synthesis was conducted to complement the Rome IV Diagnostic Criteria for IBS. Future efforts will subject these proposed AAPT criteria to systematic empirical evaluation of their feasibility, reliability, and validity. The AAPT IBS criteria are part of an evidence-based classification system that provides a consistent vocabulary regarding diagnostic criteria, common features, comorbidities, consequences, and putative mechanisms of the disorder. A similar approach is being applied to other chronic and often debilitating abdominal, pelvic, and urogenital pain conditions. Perspective: The AAPT's goal is to develop an evidence-based taxonomy for chronic pain on the basis of a consistently applied multidimensional framework, and encourage experts to apply this taxonomy to specific chronic pain conditions. In this report, the taxonomy is applied to IBS, a chronic abdominal pain condition.