Encountering patients with chronic fatigue syndrome (CFS) or fibromyalgia can cause dilemmas for physicians due to the uncertainty inherent in these illnesses. The aim of this study was to investigate: (1) How physicians in a Swedish sample describe and categorise patients with CFS and fibromyalgia, (2) What the character of CFS and fibromyalgia, with regard to diagnosing, treatment and medical knowledge/aetiology, mean to the physicians in encounters with patients, and (3) Which strategies physicians describe that they use in the encounter with these patients. Semi-structured interviews were carried out with 26 physicians, specialists in various fields who all had some experience of either CFS or fibromyalgia. The results suggest that there is a discrepancy between the ideal role of the physician and reality in the everyday work in interaction with these patients. This may lead to the professional role being questioned. Different strategies are developed to handle the encounters with these patients. The results also illuminate the physician's interpretations of patients in moralising terms. Conditions given the status of illness were regarded, for example, as less serious by the physicians than those with disease status. Scepticism was expressed regarding especially CFS, but also fibromyalgia. Moreover, it is shown how the patients are characterised by the physicians as ambitious, active, illness focused, demanding and medicalising. The patient groups in question do not always gain full access to the sick-role, in part as a consequence of the conditions not being defined as diseases. ⌐ 2003 Elsevier Science Ltd. All rights reserved.