Perfectionism can be a problem in its own right and it can impede the progress of treatment of Axis I disorders. This study reports on a preliminary randomised controlled trial of cognitive-behaviour therapy (CBT) for "clinical perfectionism". Twenty participants were randomly assigned to either immediate treatment (IT) (n=10) or a wait list (NL) (n=10). Treatment consisted of ten sessions of CBT over eight weeks. Two participants did not complete the follow-up assessments (10%). Fifteen of the original 20 participants (75%) were clinically significantly improved after treatment and the effect size was large (1.8). Treatment gains were maintained at 8-week and 16-week follow-up.