Background: Cognitive-behavioural models of chronic fatigue syndrome (CFS) suggest that personality factors such as perfectionism and high moral standards may contribute to the development of CFS. Aims: To investigate cognitive, behavioural and emotional processing risk factors for CFS. Method: CFS patients (n = 67) at a UK specialist clinic completed questionnaires about psychological characteristics both currently and retrospectively (6 months pre-CFS onset). Responses were compared with those of healthy individuals (n = 73) who rated their current characteristics. Forty-four relatives retrospectively rated the pre-morbid psychological characteristics of the CFS participants. Results: CFS patients showed similar levels of current perfectionism to controls, though higher pre-morbid perfectionism. CFS patients showed greater self-sacrificial beliefs and more unhelpful beliefs about experiencing and expressing negative emotions, both currently but more markedly prior to onset. In the 6 months pre-illness onset, CFS patients showed more disruption to their primary goal and greater general stress than controls. Ratings of pre-morbid psychological characteristics by relatives were consistent with patients’ self-reports. The extent of overinvestment in one goal was significantly associated with fatigue. Conclusions: Perfectionism, self-sacrificial tendencies, unhelpful beliefs about emotions, and perceived stress may be present to a greater extent pre-morbidly in CFS patients compared with healthy individuals.