The World Health Organization's International Classification of Function (ICF) is a tool to characterize and illuminate better the full of array of problems a patient faces when affected by disease. Specifying these problems is a particular challenge in a disease like systemic lupus erythematosus (SLE) because of the wide variety in organ systems involved, its variable activity and severity, and considerable ethnic and local differences. The authors of this manuscript believe, however, that a broader understanding will prove essential for optimal patient care, and that there is sufficient experience now in defining ICF Core Sets to successfully complete core sets for SLE. Therefore, we will embark on an international project for developing ICF Core Sets for SLE, which we here delineate. This development will include two versions: 1) The Brief ICF Core Set for SLE will be a very focused list of categories essential for SLE clinical trials; and 2) The Comprehensive ICF Core Set will be much broader and useful for guiding multidisciplinary assessment in patients with SLE. Both Core Sets will be developed in a formal decision-making and consensus process of health professionals integrating evidence gathered from preliminary studies. The final definition of the Core Sets will occur at a consensus conference which will integrate: i) a systematic review of the literature regarding the outcome measures used in clinical trials and selected observational studies; ii) focus groups or semi-structured interviews with SLE patients; iii) a Delphi exercise with world wide involvement of experts; and iv) the evidence from empirical studies. The development of these SLE ICF Core Sets is designed to be an inclusive, open, worldwide process. We therefore invite both SLE clinical experts and SLE patients to participate actively.