Objective: Activity pacing is frequently advised as a coping strategy for the management of chronic conditions (such as chronic low back pain, chronic widespread pain and chronic fatigue syndrome/myalgic encephalomyelitis). Despite anecdotal support for activity pacing, there is limited and conflicting research evidence into the efficacy of this strategy. There is no consensus on the interpretation of 'pacing' due to diverse descriptions, including strategies that encourage both increasing and decreasing activities. Furthermore, at present, there are few validated scales to measure how patients pace their activities. The aim of this study was to undertake the first stage in the development of a comprehensive tool that assesses the multi-faceted nature of pacing among patients with chronic conditions. Design: Three-round Delphi technique. Participants: Expert panel based in the UK including patients and clinicians. Results: The 42 participants who completed three rounds of Delphi included 4 patients, 3 nurses, 26 physiotherapists and 9 occupational therapists. The 38 questions that reached consensus to be included in the questionnaire encompassed a number of different facets of pacing, for example, breaking down tasks, not over-doing activities, and gradually increasing activities. Conclusions: To our knowledge, this is the first study that has engaged both patients and clinicians in a Delphi technique to develop an activity pacing questionnaire. In contrast to existing pacing scales, our questionnaire appears to contain a number of distinct facets of pacing. Further study is being undertaken to engage patients in the exploration of the validity, reliability and acceptability of the questionnaire.