We describe the results of a randomized controlled trial to assess effectiveness of an anger management group programme, employing a cognitive behavioural framework that was run by the Psychology Service. The treatment group was compared with a control group on a waiting list. The trial was performed at the Southampton CBT Service. The treatment group received a cognitive behavioural anger management programme, initially based on Novaco's approach, but with further development of the motivational components. The control group received no treatment and was on a waiting list. The Novaco Anger Assessment Scale (NAS), State-Trait Anger Expression Inventory (STAXI), Evaluative Beliefs Scale (EBS), Hospital Anxiety and Depression Scale (HAD) and the Clinical Outcomes in Routine Evaluations (CORE) were used to measure anger, belief about self and others, anxiety and depression, and physical and psychological wellbeing. Clients in the anger management group showed statistically significant changes on STAXI, NAS, CORE and EBS subscales at the end of the therapy. The change in depression and anxiety on HAD (depression and anxiety) was not statistically significant. It was not possible to carry out analyses at follow-up due to high dropout rates. We concluded that an anger management programme using CBT was helpful in reducing anger and overall psychopathology.