BACKGROUND: In Gjoevik, a Norwegian town with 28,000 inhabitants, general practitioners (GPs) have taken more responsibility for Methadone Maintenance Treatment (MMT) of heroin addicts than usual in Norway. We have assessed the treatment results in Gjoevik by comparing the fraction of patients who continue with treatment (retention in treatment, from 1999 to 2003), frequency of patient contact with professionals and the treatment outcome with the results for the rest of Norway. MATERIAL AND METHODS: In Norway, annual treatment results are reported for every MMT patient and the results are entered into a national register. This study is based on data in the national register from 2003. RESULTS: Retention is significantly higher in Gjoevik (93% vs. 77%) than in the rest of Norway. Patients have more contact with their GP in Gjoevik, while contact with local social service and so-called "responsibility groups" (organised cooperation between patient and professionals) are on the same level as for the country as a whole. The patients have less contact with specialized substance abuse and MMT centres than the average Norwegian patient. Treatment outcome regarding social rehabilitation (housing, source of income, occupation) and control of addictive behaviour (injecting drugs, opiate and illegal benzodiazepines in urine tests and overall assessment of drug behaviour) is close to the national average. INTERPRETATION: This may indicate that MMT programs with considerable delegation of treatment responsibility to GPs and local social service, can function as well as programs that rely more on specialised MMT-centres.