question: The novel coronavirus, COVID-19, has dramatically impacted clinical service delivery, particularly substance use treatment The Families Actively Improving Relationships (FAIR) program is an action-oriented, evidence-based behavioral treatment for opioid and methamphetamine disorders in parents involved in the child welfare (CW) system A seven-clinician team operates out of a Medicaid-funded clinic, primarily delivering services in the community Attending to underlying mechanisms of FAIR's intervention strategies that promote client engagement and clinical outcomes, FAIR rapidly adapted it procedures in response to COVID-19-onset disruptions This study analyzes administrative records and Medicaid claims data from January 2019 to July 2020, including 157 clients and 17,449 claims We considered COVID-19 presence as March–July 2020 The study examined changes in the frequency and reimbursement volume of FAIR service delivery pre- and postonset of COVID-19 Although average monthly reimbursement per clinician did not significantly decline, reimbursement per client significantly declined by 31% (pre: $1005 [$732];post: $698 [$546], p &lt; 001) Clinicians delivered services on significantly more days per month during COVID-19 (mean (sd) = 16 73 (6 33);20 26 (7 24), t(127) = −2 70, p &lt; 01) Average clinician caseload size was stable, as was the average monthly service receipt days for clients Thus, this study attributes reductions in reimbursement per client when FAIR provided services remotely to the elimination of in-person billable services and reductions in session length, but not in frequency Medicaid-funded clinics and community-based substance use treatment interventions such as FAIR can successfully sustain and implement substance use treatment practices with deliberate, rapid adaptation to ensure that families receive needed supports in the face of contextual crises