To assess the effectiveness of teaching general practitioners skills in brief cognitive behaviour therapy. Parallel group, cluster randomised, controlled trial of an educational package on cognitive behaviour therapy. General practices in north London. 84 general practitioner principals and 272 patients attending their practices who scored above the threshold for psychological distress on the hospital anxiety and depression scale. A training package of four half days on brief cognitive behaviour therapy. Scores on the depression attitude questionnaire (general practitioners) and the Beck depression inventory (patients). Doctors' knowledge of depression and attitudes towards its treatment showed no major difference between intervention and control groups after 6 months. The training had no discernible impact on patients' outcomes. General practitioners may require more training and support than a basic educational package on brief cognitive behaviour therapy to acquire skills to help patients with depression.