Background. One of the many controversies surrounding chronic fatigue syndrome (CFS) is the possible impact of the diagnostic label: is it disabling or enabling? In this paper, we discuss the pros and cons of labelling CFS. Method. A narrative synthesis of the literature. Results. Diagnosed CFS patients have a worse prognosis than fatigue syndrome patients without such a label. The ways in which CFS patients perceive themselves, label their symptoms and appraise stressors may perpetuate or exacerbate their symptoms, a process that involves psychological, psychosocial and cultural factors. Labels can also lead to conflicts with doctors who fear diagnosis might lead to worse outcomes. However, on the other hand, finding a label that fits one's condition can provide meaning, emotional relief and recognition, whilst the denial of the diagnosis of CFS in those who have already reached their own conclusion can be very counter productive. The act of diagnosis therefore seems to be a trade-off between empowerment, illness validation and group support, contrasted with the risk of diagnosis as self-fulfilling prophecy of non-recovery. Conclusions. The answer to th e question of 'to label or not to label' may turn out to depend not on the label, but on what that label implies. It is acceptable and often beneficial to make diagnoses such as CFS, provided that this is the beginning, and not the end, of the therapeutic encounter.