Research has demonstrated the effectiveness of computerized cognitive behaviour therapy (cCBT) for depression and anxiety in adults, but there has been little work with children and adolescents. Aims: To describe the development of a cCBT intervention (Think, Feel, Do) for young people, and preliminary outcomes and feedback from a pilot randomized controlled trial. Method: Twenty participants aged 11 to 16 with depression or anxiety were randomized to receive cCBT immediately or after a delay. Standardized measures were used to assess self-reported anxiety, depression, self-esteem and cognitions, as well as parent rated strengths and difficulties. A feedback form was also completed to assess young people's views of the programme. Results: A total of 15 participants completed the pre and post assessments in the trial, and 17 provided feedback on the intervention. Paired samples t-tests demonstrated significant improvements on 3 subscales in the control condition, compared to 7 subscales in the cCBT condition. Feedback showed moderate to high satisfaction for participants. Conclusions: This study provides encouraging preliminary results for the effectiveness and acceptability of cCBT with this age group.