OBJECTIVES: Studies consistently show high relapse rates (25% - 35%) among chemical dependence patients.  Relapse is especially problematic for patients diagnosed with opioid dependence (OD), which has often been characterized as a chronic relapsing disorder.  The purpose of the present study was to examine the effect of compliance with buprenorphine-medication assisted treatment (B-MAT) on relapse among a sample of opioid dependent patients. METHODS: OD patients new to B-MAT (N=554) completed the Addiction Severity Index (ASI) at baseline, 1, 2, 3, and 6 months post-enrollment.  The ASI is a semi-structured interview designed to measure problem severity in 7 functional areas known to be affected by alcohol and drug dependence.  One year follow-up data will be presented in the poster; however, only 6 month data were available at the time of submission.  Compliance with B-MAT was defined as taking medication on at least 80% of the days over the past month.  Relapse was defined as use of opioids, including heroin, methadone, or pharmaceutical opioids, after an initial period of no use. RESULTS: Patients who were compliant with B-MAT were significantly less likely to relapse compared to subjects who were non-compliant with B-MAT (24.8% vs. 57.8%, χ2(1, n = 493) = 37.49, p <0.001). Differences in baseline characteristics between the compliance groups and the relapse groups were also revealing.  Patients who relapsed had significantly higher baseline medical, legal, psychiatric, and family composites scores compared to those who did not relapse (p’s <0.05), indicating greater problem severity in these areas.   CONCLUSIONS: Compliance with B-MAT for six months seems to reduce the likelihood of relapse in OD patients.  Difference in patient characteristics may be used to help providers identify patients who need higher levels of care to avoid relapse. Future studies should examine relapse rates in patients who have successfully tapered off B-MAT.