OBJECTIVES: To compare the costs and effectiveness of Methadone Maintenance Treatment (MMT) and Buprenorphine Maintenance Treatment (BMT) among stabilized opioid dependent patients. METHODS: A cost analysis was performed. One hundred forty-five patients, on either treatment between 1 month and 12 months, were selected from 28 randomly chosen community pharmacies. Questionnaires were issued to 135 community pharmacies, of which 67 (including these 28) validly responded for costing these 2 services. (24 of the pharmacies did not provide either of these services.) A treatment sector perspective was chosen. Costs incurred at the Commonwealth government, pharmacy and patient levels were investigated. ANOVA models were applied to test for differences while controlling for length on program. Effectiveness was measured as change in opioid-free days. RESULTS: At the Commonwealth government level, costs of the medicines and doctor visits were taken into account. The estimated monthly cost (SD) per methadone patient was AUD$62.8 ($32.6) and AUD$169.0 ($33.7) per buprenorphine patient. Costs of medicines comparing treatments showed a significant difference (p=0.000) but doctor visits showed none (p=0.609).At the pharmacy level, the estimated monthly cost (SD) of one MMT patient was AUD$104.3 ($24.5) and AUD$128.2 ($40.3) per BMT patient (p=0.005). At the patient level, median monthly fees (range) for dispensing and transportation were $128.0 ($61.3-$234.7) per MMT patient whereas $156.0 ($66.0-$394.7) per BMT patient. The difference lay in the monthly transportation fee (p=0.008). During the first year of treatment, estimated mean total cost (SD) on one MMT patient was $306.2 ($51.2) monthly, but $465.8 ($66.4) for one BMT patient (p=0.000). The average change in opioid-free days (SD) out of 30 was 27.7 (5.7) days for MMT, and 26.0 (7.2) days for BMT patients (p=0.102). CONCLUSIONS: Significant differences in costs of MMT and BMT were identified. MMT was less costly but resulted in the same overall change in opioid-free days.