Self-help materials can be offered to clients/patients either for use alone (unsupported self-help) or to support work with a health care practitioner (supported self-help). Structured self-help materials that use a Cognitive Behaviour Therapy (CBT) treatment approach have been shown to be clinically effective. We report a national survey of all 500 cognitive and behavioural psychotherapists registered with the British Association for Behavioural and Cognitive Psychotherapies, the lead organisation for CBT in the United Kingdom. A total of 265 therapists responded (53%). Self-help materials were used by 88.7% of therapists and were mostly provided as a supplement to individual therapy. Self-help was most frequently used to help patients experiencing depression, anxiety and obsessive compulsive disorder and was largely delivered using paper-based formats. The majority of self-help materials used a CBT approach. Only 36.2% of therapists had been trained in how to use self-help treatments, and those who had received training recommended self-help treatments to more clients/patients per week and rated self-help approaches as being significantly more helpful than those who had not received training.