As the number of pathological gamblers has increased recently, the need for effective treatment has become more evident. The aim of this study was to evaluate the effectiveness of a short-term cognitive-behavioural group therapy programme for pathological gamblers. Fourteen subjects (three females and 11 males), who met the criteria for pathological gambling in accordance with the Diagnostic and Statistical Manual of Mental Disorders IV, were randomly assigned to a Treatment Group (n=7) or a waiting list Control Group (n=7). An experimental design with three repeated measures was used (pre-treatment, post-treatment/post-waiting list and follow-up). The dependent variables were DSM-IV Criteria for Pathological Gambling, Money Spent on Gambling During the Last Week and Gamblers Inventory of Negative Consequences. The Treatment Group improved on the DSM-IV Criteria for Pathological Gambling, but did not show a significant improvement on Money Spent on Gambling During the Last week from pre-treatment to post-treatment. Combining both groups at 3-months follow-up, there was a significant improvement on all three variables from pre-treatment to follow-up. The results of this controlled study indicate that a short-term cognitive-behavioural group treatment for pathological gamblers had an effect.