Objective: Family responses to patients with chronic fatigue syndrome (CFS) may influence the course of the disorder and family members themselves are likely to be adversely affected. However, the beliefs and responses of relatives of CFS patients have been under-researched. The aim of this study was to produce an easy-to-administer questionnaire to assess the responses of family members to people with CFS. Methods: Seventy-eight people, all close relatives of (physician- diagnosed) CFS sufferers, completed the first version of the Family Response Questionnaire (FRQ). Results: Examination of the correlation matrix and a cluster analysis of the items support four scales rather than the original five. The four response scales were labelled: sympathetic-empathic, active engagement, rejecting -hostile, and concern with self. Measures of test-retest and internal reliability were high. Participants found the items both comprehensible and relevant to their experiences of living with people with CFS. Conclusion: The new version of the FRQ will be useful in further examination of the responses of CFS on individuals and their families. (C) 2001 Elsevier Science Inc. All rights reserved.