BACKGROUND: The relative efficacy of different psychological treatments for chronic post-traumatic stress disorder (PTSD) is unclear. AIMS: To determine the efficacy of specific psychological treatments for chronic PTSD. METHOD: In a systematic review of randomised controlled trials, eligible studies were assessed against methodological quality criteria and data were extracted and analysed. RESULTS: Thirty-eight randomised controlled trials were included in the meta-analysis. Trauma-focused cognitive-behavioural therapy (TFCBT), eye movement desensitisation and reprocessing (EMDR), stress management and group cognitive-behavioural therapy improved PTSD symptoms more than waiting-list or usual care. There was inconclusive evidence regarding other therapies. There was no evidence of a difference in efficacy between TFCBT and EMDR but there was some evidence that TFCBT and EMDR were superior to stress management and other therapies, and that stress management was superior to other therapies. CONCLUSIONS: The first-line psychological treatment for PTSD should be trauma-focused (TFCBT or EMDR).