The aim of this paper was to test the long-term contribution of cognitive-behavioural therapy to the treatment of mixed anxiety-depression disorder. Fifty-seven patients, selected according to DSM-IV diagnostic criteria, were assigned to: 1) cognitive-behavioural therapy; 2) combined therapy (drug and cognitive-behavioural therapy); or 3) a standard drug therapy control group. A multigroup experimental design with repeated measures of assessment (pretreatment, posttreatment, and 3-, 6- and 12 month follow-ups) was used. Most patients who were treated (71%) in experimental groups showed significant improvement at the 12-month follow-up, but there were no differences between the two therapeutic modes. No improvement was shown by the control-group participants at the 6-month follow-up. The results of the present trial do not support the beneficial effects of drug therapy by itself for this disorder. Finally, several topics that may contribute to future research in this field are discussed.