Aims and method To establish the competency of psychiatric trainees in delivering cognitive-behavioural therapy (CBT) to selected cases, following introductory lectures and supervision. Supervisor reports of trainees rotating through a national psychiatric hospital over 8.5 years were reviewed along with revised Cognitive Therapy Scale (CTS-R) ratings where available. Independent t-test was used to compare variables. Results Structured supervision reports were available for 52 of 55 (95%) trainees. The mean result (4.6, s.d. = 0.9) was at or above the accepted level for competency (≥3) for participating trainees. Available CTS-R ratings (n = 22) supported the supervisor report findings for those particular trainees. Clinical implications This study indicates that trainees under supervision can provide meaningful clinical interventions when delivering CBT to selected cases. The costs of supervision need to be judged against these clinical gains.