Problems in functioning are frequently seen in survivors of head and neck cancer (HNC) and proof to have increasing impact on their quality of life. With the approval of the International Classification of Functioning, Disability and Health (ICF) by the World Health Assembly in May 2001, we can now rely on a globally accepted framework and classification system based on a bio-psycho-social mode to assess and compare functional outcome. To make the ICF-classification with more than 1.400 categories applicable to every-day clinical practice, ICF core sets are established. The objective of this paper is to outline the proposed development process for the ICF core set for HNC and to invite international experts to participate in this process. The ICF core set will be defined at a Consensus conference, which will integrate evidence from preparatory studies, namely: (a) a systematic literature review regarding the outcome measures of clinical trails and observational studies, (b) semi-structured patient interviews, (c) international experts participating in a internet-based survey and (d) cross-sectional, multi-center studies for clinical applicability. To validate the ICF core set field-testing will follow. The ICF provides useful standards of clinical rehabilitation practice, research and teaching. Its application stimulates comparability of outcome parameters, eventually improving understanding of functioning and disability. The ICF can function as a new language, simplifying communication and cooperation between various professional backgrounds and between health professionals and their patients eventually leading to a more effective and economic rehabilitation. The ICF core set for HNC is designed to translate the benefits of the ICF into clinical routine. The development of ICF core sets is an inclusive and open process. Anyone who wishes to actively participate is invited to contact the project coordinator. Individuals, institutions and associations can be formally associated as partners of the project.