BACKGROUND: Most scientific journals practise anonymous peer review. There is no evidence, however, that this is any better than an open system. AIMS: To evaluate the feasibility of an open peer review system. METHOD: Reviewers for the British Journal of Psychiatry were asked whether they would agree to have their name revealed to the authors whose papers they review; 408 manuscripts assigned to reviewers who agreed were randomised to signed or unsigned groups. We measured review quality, tone, recommendation for publication and time taken to complete each review. RESULTS: A total of 245 reviewers (76%) agreed to sign. Signed reviews were of higher quality, were more courteous and took longer to complete than unsigned reviews. Reviewers who signed were more likely to recommend publication. CONCLUSIONS: This study supports the feasibility of an open peer review system and identifies such a system's potential drawbacks.