The inflammatory bowel diseases (IBDs) are associated with a reduced quality of life. The impact of IBD on disability remains largely unknown. With the International Classification of Functioning, Disability, and Health (ICF) of the World Health Organization (WHO), we can now rely on a globally agreed-upon framework and system for classifying the typical spectrum of problems in the functioning of persons with a specific disease given the environmental context in which they live. The aim of this article is to outline the methods to be utilized to develop ICF Core Sets for IBD. The project is a cooperation between the ICF Research Branch of the WHO, the IPNIC group, the International Society of Physical Rehabilitation Medicine (ISPRM), and the International Organization on Inflammatory Bowel Disease (IOIBD). Four worldwide studies will be conducted from 2009 to 2010. ICF categories relevant for IBD will be identified by systematic literature review of outcomes and measures used in IBD research, semistructured patient interviews, Internet-based expert survey, and cross-sectional study for clinical applicability. The final definition of ICF Core Sets for IBD will be determined at a Consensus Conference. Field testing will then be used to validate the ICF Core Sets. ICF Core Sets are being designed to provide useful standards for research and clinical practice. This tool will enable research that improves understanding of functioning, disability, and health in IBD, and may lead to interventions to improve and maintain functioning and minimize disability among IBD patients throughout the world.