Objective: The present study examines the application of auricular acupuncture as an additional treatment during methadone maintenance treatment for opiate addicts. Methods: A naturalistic observational study analysed the course of 114 clients who started acupuncture treatment between October 1998 and December 1999 in an addiction outpatient clinic in Hamburg-Altona. The study focused on analysing effects of acupuncture on drug use behaviour, withdrawal symptoms and general wellbeing. Results: Clients remained in treatment on average about 13 weeks with slightly more than one contact per week. The results show a reduction of withdrawal symptoms and substance craving as well as an improvement of emotional well-being. The additional use of cocaine and heroin as well as intravenous use decreased during the course of treatment. In the analysis for all participants the effects are not very strong, but those with additional use of multiple drugs seem to profit from acupuncture. Conclusions: The results allow the conclusion, that acupuncture can show an effect in improving drug treatment. Considering results for drug addicts with highly problematic use patterns, acupuncture should be implemented and further evaluated in maintenance treatment as well as in low threshold treatment settings.