OBJECTIVES: To identify an optimal minimum length of treatment (LOT) for opioid dependence with buprenorphine in order to begin the evidentiary discussion of appropriate treatment length.   METHODS: A retrospective claims analysis was conducted on the (January 2007 – June 2014) Truven Health Analytics MarketScan® Medicaid Research Database in all ICD diagnoses related to opioid dependent adults 16-65 years old (N=23,022), who received BMAT for at least 3 months and whose treatment was medically  discontinued.  The assumption was that higher resource use and costs after the planned end of treatment represented inadequate treatment time, compared to lower resource use and costs which represented the optimal minimum LOT. The study compared resource use (number of inpatient admissions, outpatient visits and prescriptions filled) and the associated costs for patients who remained in their plans for 6 and 12 months post BMAT. Comparisons were made between the following LOT groups: 3-5, 6-8, 9-11, 12-17, 18-23, and 24+ months. Regression analyses was conducted to test influence of key variables (i.e. LOT) on resource use and healthcare costs. RESULTS: Regression analyses demonstrated a strong negative association with higher resource use and total healthcare costs (i.e. longer treatment duration is associated with lower post-BMAT resource use and costs). Resource use correlation coefficient analysis identified outpatient services as the most influential parameter (integrative parameter). When combined, analyses of the proportion of patients with high resource use and a mean resource use, the study demonstrated that 9-17 months were the optimal minimum LOT in the general population. Analysis of the total healthcare costs and the subgroup with high total healthcare costs both indicated the optimal minimum LOT was 12-17 months.  CONCLUSIONS: This study is the first retrospective evidence that identifies the optimal minimum length of treatment with buprenorphine to treat opioid dependence. For the general population, it appears that the optimal minimum length of treatment with buprenorphine is 12-17 months.