BackgroundCognitive behavioural therapy (CBT) has been used in the treatment of alcohol use disorder (AUD), generally in individual or group therapy, but not via computer.AimThis study examined the effectiveness of an interactive, personalised, computer-based CBT therapy in a randomised control trial.MethodsWe studied a group of 55 patients with AUD, randomised to either 5-hour-long computerised CBT sessions or a placebo cognitive-stimulating session, together with a 4-week inpatient rehabilitation treatment, and followed them for 3 months.ResultsThere was a high degree of patient adherence to the protocol. Both groups did well, with a significant fall in alcohol outcome measures including number of drinks per drinking day, and number of drinking days, and an increase in abstinence rates in both groups to an equivalent level. The CBT group attended alcoholics anonymous groups more frequently, and had significant alterations in their alcohol self-efficacy outcomes, which correlated with their drinking outcomes. We concluded that computerised CBT is a potentially useful clinical tool that warrants further investigation in different treatment settings for AUD.