The aim of this case report is to describe the impact of an intervention for clinical perfectionism, derived from a new cognitive-behavioural analysis, in a patient with binge-eating disorder. It was hypothesized that clinical perfectionism was contributing to the maintenance of the eating disorder, and on this basis it was predicted that reducing clinical perfectionism would improve her eating disorder psychopathology. Standardized independent assessments were found to be consistent with this hypothesis, in that clinical perfectionism and eating disorder psychopathology improved over an eight-session intervention and improvements were largely maintained at 5-month follow-up.