Healthcare professionals responsible for patients with gastrointestinal diseases need a particular level of nursing knowledge and abilities to ensure excellent care. This study aims to propose a set of core competencies for the gastroenterology nursing specialists (GNS) in China. This research integrates quantitative and qualitative research methods. Literature review, semistructured interview, and the Delphi approach were used to develop the core competency items of GNS in China. SPSS 16.0 was used to analyze the data. Finally, 28 of 30 experts participated in the study resulting in a consensual list containing 7 domains (clinical nursing practice, communication and collaboration, education and counseling, critical thinking, leadership, ethical and legal practice, and professional development), 23 aspects, and 66 competencies required for GNS. The authority coefficient (Cr) of the consensus was 0.77, and the Kendall (W) value of each level of competencies all scored above 0.5. Results of the study can serve as a foundation of work performance evaluation for GNS as well as promote nurses' professional development.