7. Abstract Jails provide an optimal setting for intervening with individuals with opioid use disorders (OUD), given the high volume of offenders with OUD, and their high risk of relapse to opioids following their release to the community. It is imperative that individuals with OUD are linked to community-based medication assisted treatment (MAT) upon their re-entry, as well as receive support for their ongoing treatment retention and recovery. The proposed experiment will test an adapted version of an evidence-based intervention, the Recovery Management Checkups (RMC) model, which provides quarterly check-ups and assistance with treatment retention and re-linkage as indicated at the quarterly check-ups. The RMC-Adapted will adjust the frequency and intensity of check-ups based on the individual?s assessed need for treatment, thereby reducing (or lengthening) the time between check-ups for those with (or without) indicators of treatment need. The proposed experiment will compare treatment linkage and retention rates as well as public health and public safety outcomes of 750 male and female offenders randomly assigned to 1 of 3 groups upon release from jail: a) a re-entry as usual (control), b) the original RMC, and c) a RMC-Adaptive version tailored to the participant?s need for treatment. The study will be conducted in collaboration with 6 county jails in Illinois and the MAT providers that currently provide pre- and post-release MAT to offenders with OUD. Pre-release, participants will be screened for history of OUD and eligibility for MAT. All participants will receive research follow-up interviews quarterly for 2 years, which will also include urine testing and records checks (treatment, mortality, recidivism). The study aims are to evaluate: (1) the direct effects of RMC and/or RMC-Adaptive on the OUD service cascade of care (initiation, engagement, retention, re-linkage, and months of MAT participation); (2) the indirect effects of RMC and/or RMC-Adaptive (via months of MAT participation) on public health outcomes (days of opioid use, OUD symptoms, quality of life and the cost of health-care utilization); (3) the indirect effects of RMC and/or RMC-Adaptive (via months of MAT and public health outcomes) on public safety outcomes (illegal activity, re-arrest, re-incarceration, and cost of crime); and (4) the incremental costs and cost-effectiveness of the control vs. RMC vs. RMC-Adaptive in terms of both public health outcomes (days of opioid use, quality adjusted life years [QALYs], cost-of-health-care utilization) and public safety outcomes (re-incarceration and cost of crime). The study will determine if tailoring the checkups to individual?s need for treatment leads to more efficient targeting of resources to those in need, reduces the intervention burden on those with lower need, and results in an improved overall effectiveness and cost-effectiveness of RMC checkups.