Background Computerised cognitive–behavioural therapy (CCBT) is used for treating depression and provides a potentially useful alternative to therapist cognitive–behavioural therapy (CBT). Aims To systematically review the evidence for the effectiveness of CCBT for the treatment of mild to moderate depression. Method Electronic databases were searched to identify randomised controlled trials. Selected studies were quality assessed and data extracted by two reviewers. Results Four studies of three computer software packages met the inclusion criteria. Comparators were treatment as usual, using a depression education website and an attention placebo. Conclusions There is some evidence to support the effectiveness of CCBT for the treatment of depression. However, all studies were associated with considerable drop-out rates and little evidence was presented regarding participants' preferences and the acceptability of the therapy. More research is needed to determine the place of CCBT in the potential range of treatment options offered to individuals with depression.