Depression, anxiety disorders and phobias are common mental health problems associated with considerable occupational and interpersonal impairment. Although there is substantial evidence to support the use of cognitive behaviour therapy (CBT) in the treatment of these disorders, access is limited. Computerized cognitive behaviour therapy (CCBT) is one of a variety of aids to self-management that offer patients the potential benefits of CBT with less therapist involvement than therapist led CBT (TCBT). In this systematic review of the efficacy of CCBT, 16 studies were identified. Of these 11 were RCTS and the remaining 5 were pilot or cohort studies. The quality of studies ranged from poor to moderate (although the criteria used precluded the highest rating). In the studies comparing CCBT with TCBT, five studies showed CCBT have equivalent outcomes to TCBT. One study of depressed inpatients found TCBT to be significantly more effective than CCBT. Four studies found CCBT to be more effective than treatment as usual (TAU). Two studies found CCBT to be no more effective than TAU. Two studies compared CCBT with bibliotherapy. Of these, one study found CCBT to be as effective as bibliotherapy and one found bibliotherapy to be significantly more effective than CCBT on some outcome measures. Although the results of this review are not conclusive, CCBT is potentially useful in the treatment of anxiety disorders, depression and phobias. From the results of this review, we make three recommendations to improve the quality of research in this field, and suggest four areas requiring further research.