Functioning is increasingly being taken into account for evaluating the impact of multiple sclerosis (MS) on the individual and the effectiveness of treatment and rehabilitation. With the International Classification of Functioning, Disability and Health (ICF), we can now rely on a globally-agreed-upon framework and system for classifying the typical spectrum of problems in functioning of persons given the environmental context in which they live. ICF Core Sets are lists of ICF categories selected to capture those aspects of functioning that are most likely to be affected by specific diseases. The objective of this document is to outline the development process for the ICF Core Sets for MS. The ICF Core Sets for MS will be defined at an ICF Core Set Consensus Conference, which will integrate evidence from preparatory studies, namely: a) a systematic review on parameters reported in MS studies; b) a qualitative study using focus groups and individual interviews with individuals with MS; c) an expert survey with international health professionals participating and d) an empirical cross-sectional study. The ICF Core Sets for MS are being designed with the goal of providing useful standards for research and clinical practice.