AIM: The aim of this study was to identify candidate categories from the International Classification of Functioning, Disability and Health (ICF) to be included in the Brief ICF Core Set for low back pain (LBP) by examining their relation to general health and functionality. METHODS: This was part of an international multicentre study with 118 participating Norwegian patients with LBP. The Comprehensive ICF Core Set for LBP was filled in by health professionals. The patients reported their health-related quality of life in the Medical Outcome Study Short Form 36 (SF-36) and function in the Oswestry Disability Index. Two questions regarding the patient's general health and functioning were completed by the health professionals and the patients themselves. Regression models were developed in order to identify ICF categories explaining most of the variance of the criterion measures. RESULTS: Twelve ICF categories remained as significant explanatory factors according to the eight regression models, four of which were not included in a previously proposed Brief ICF Core Set for LBP. CONCLUSIONS: The present study complements the development of the Brief ICF Core Set for LBP, and indicates a minimum number of categories needed to explain LBP patients' functioning and health. Further elaboration of the Brief ICF Core Set for LBP with multinational data is needed.