To study the prevalence of problem drinking among patients undergoing methadone treatment programmes, 170 patients were assessed using the self-administered alcohol screening test (mSAAST). Fifty-three (31.9%) patients scored 7 or more on the mSAAST, indicating actual or potential drinking problems. There was a slight tendency for these to be male. Patients who abused alcohol also tended to use benzodiazepines irrespective of sex. The results of the study seem to indicate that the prevalence of dual alcohol and opiate use is high amongst patients attending drug dependency units. Furthermore comprehensive research is required in order to plan effective treatment for these dual addicted patients.