INTRODUCTION: Comorbid substance related disorders are a major health problem for patients in opioid maintenance treatment (OMT). It was investigated whether a reinforcement scheme adapted to the regulatory and financial restrictions of routine treatment reduces concomitant drug use. METHODS: OMT patients from 7 clinics who were using cocaine, benzodiazepines, heroin or amphetamines were randomly allocated to either treatment as usual (n = 64) or treatment with an additional escalating reinforcement scheme (n = 72) in which a patient's number of weekly take-home dosages was increased after 1, 4, 8 and 12 consecutive weeks with drug-free urine specimens. Trial duration was 26 weeks. RESULTS: Completion rates were 64% for controls and 62.5% in the experimental group. Mean number of drug-free weeks was 11.3 (SD 8.5) for the control group and 9.8 (8.9) for the experimental group (p = 0.30). CONCLUSION: The intervention was not effective compared to routine treatment. Additional features might be necessary to achieve an effect, e.g. a higher frequency of urine sampling or use of other reinforcers. It has to be further investigated how interventions which have been proven effective in experimental studies can successfully be adapted to routine care conditions.