OBJECTIVES: Buprenorphine-medication assisted treatment (B-MAT) is an effective treatment for OD, but is hypothesized to have the greatest impact on those patients who are compliant. This analysis was conducted to compare economic costs and benefits between B-MAT compliant and non-compliant OD members. METHODS: A longitudinal, multivariate analysis was conducted using service use claims data among a sample of Aetna members with full benefit coverage and at least one diagnoses of OD during the 48 month measurement period (Q1 2006 to Q4 2009).  Medication possession ratio (MPR) was calculated for the sample (n = 725).  Members with an MPR ≥ .80 were classified as compliant (n = 324), with the balance classified as non-compliant (n = 401).  Two six-month measurement periods were constructed around the index date. RESULTS: After B-MAT induction, compared to non-compliant B-MAT members, compliant members increased their total number of prescriptions filled by an average of 2.57 per member (P = 0.007).  However, B-MAT compliant members showed decreases in inpatient hospital admissions (-0.62), inpatient hospital days (-4.77), and emergency room visits (-0.42; P’s <0.001).  Concerning healthcare costs, compliant B-MAT members increased their spend at the pharmacy compared to non-compliant B-MAT members by $1,059 per member (P <0.001), but decreased inpatient hospital costs (-$9,623) and ER costs (-$1,068; P’s <0.001).  Overall, compliant B-MAT members spent a total of $14,448 less (P<0.001) per member over the first six months of treatment. CONCLUSIONS: Though compliant B-MAT patients incur higher pharmacy and costs, they use fewer expensive health care services in other areas, resulting in an overall positive cost-benefit conclusion for B-MAT.  Compliance with medication-assisted treatment is essential for patient recovery, but given that less than half of the sample had an MPR ≥ .80, additional treatment ancillaries or disease management programs may be needed to increase patient compliance.