Background Over the past 25 years, the United States has experienced an opioid epidemic that has cost hundreds of thousands of lives and which now constitutes as the worst drug overdose epidemic in U.S. history. Increases in opioid use and abuse have been found among men and women, most age groups, and all income levels (CDC, 2017). Methadone Maintenance Treatment (MMT) is one the most effective forms of treatment for opioid addiction, and has been found to reduce substance use, the risk of HIV, overdose, and criminal behaviors (Joseph et al., 2000; Mattick, Breen, Kimber, & Davoli, 2009). Both clinical experience and research show that MMT programs suffer from low retention and patient engagement in treatment and that patients are particularly vulnerable to disengagement or withdrawal during the early stages of treatment (Baxter et al., 2013). To address this problem, Thomas Jefferson University Hospital Narcotic Addiction Rehabilitation Program (TJUH NARP) utilized funds from Governor Wolf’s administration to implement a program entitled the Center of Excellence (COE) to provide patients with increased support during the early stages of treatment. This support occurred in the form of one-on-one support from a Certified Recovery Specialist (CRS) who provided counselling, case management, and care coordination. As MMT treatment providers develop new programs such as the COE to address the problem of patient engagement and retention, it is critical that researchers assess their efficacy. In light of this, this dissertation has two specific aims. First, to examine the efficacy of COE program in improving patient retention, engagement in treatment, and opioid use. Second, to identify predictors of outcome within and across the conditions. Methods A case comparison study was conducted in which a control (N=57) and a treatment group (N=57) were compared regarding patient attendance, engagement, and opioid use. The control group consisted of a group admitted a year prior to the implementation of the COE while the treatment group received the supportive services of the COE. Data was collected from clinical documentation in the TJUH database. A convenience sample was used that consisted of all patients admitted during a specific time frame and who met criteria. Patient outcomes were analyzed through T-tests and chi-squared tests. Findings Patients within the treatment group had lower opioid use in months 1-3 (P=.02). This group also experienced lower attendance during month 1 (P=.04), month 2 (P=.05), month 3 (P=.02), and month 4 (P=.03). No other significant differences were found between groups regarding patient retention, engagement, or opioid use. However, while not significant, the treatment group had trends towards higher average medication doses (P=.13) and IOP attendance (P=.12). When outcomes were analyzed across conditions, patient admitted via transfer were found to have higher methadone doses on average when compared to patients admitted via self-referral (P=.01). Discussion The finding of reduced opioid use among the treatment group in months 1-3, as well as trends towards higher dosing and treatment attendance, suggests that the COE met with success in improving patient outcomes. At the same time, the lack of significant findings regarding patient attendance and engagement, as well as the treatment group’s lower attendance during months 1-4, suggests that the COE program implemented at TJUH NARP may not be entirely successful in meeting its goals. The significance of referral method challenges the efficacy of self-referral routes of entry into outpatient MMT. While further research is needed, these findings suggest that patients may benefit from inpatient stabilization prior to admittance into outpatient MMT.