Abstract: OBJECTIVE: To examine the post-injury utilization and cost of Veterans Affairs (VA) outpatient care in a cohort of Service Members and Veterans (SMVs) treated in VA Polytrauma Rehabilitation Centers (PRCs) for Traumatic Brain Injury (TBI). DESIGN: Analysis of merged datasets from the VA TBI Model Systems (VA-TBIMS) national database and Veterans Health Administration (VHA) outpatient utilization and cost data. SETTING: Five VA PRCs. PARTICIPANTS: VA-TBIMS participants who received inpatient rehabilitation at any of the 5 PRCs between 2010 and 2020. INTERVENTIONS: N/A MAIN OUTCOME MEASURES: Utilization and costs of VA outpatient clinics. RESULTS: Polytrauma/TBI clinics had the most SMVs (87.9%), with 54.4% also using telephone. Labs (78.6%) had the second highest, and primary care (77.1%) had the third. The 1,030 SMVs treated in PRCs had a median annual VA outpatient facility cost of $15,027. The costliest clinic type was mental health ($6,834), followed by TBI/Polytrauma ($4,747) + phone ($1,229), and physical therapy ($4,441). SMVs had a median of 4.1 years since injury. Time to care increased costs by $42 per day for inpatient rehabilitation and $29,426 5 years post-injury for outpatient care. Each additional point on the Disability Rating Scale (DRS) increased total costs by $593, while sexual dysfunction increased total costs by $8,214. CONCLUSIONS: VA PRCs are a gateway for SMVs to utilize VA Polytrauma/TBI clinic outpatient services, highlighting the VA Polytrauma System of Care as a framework for continuing critical clinical health services after inpatient rehabilitation. Indeed, time to access inpatient rehabilitation as well as outpatient care was associated with increasingly higher costs. DRS was a cost driver for SMVs treated in PRCs, consistent with previous studies of VA and Department of Defense (DoD) costs. Sexual dysfunction emerged as an important condition impacting VA outpatient costs, confirming evidence of its link to TBI and its importance to Veterans.