Traumatic brain injury (TBI) has been a major source of morbidity within military forces during the last 2 decades, but research on the relationship between TBI and medical readiness is limited. This study population included 41,442 service members from the U.S. Navy and Marine Corps who completed a Post-Deployment Health Assessment (PDHA) and a Periodic Health Assessment (PHA). Presence of TBI was ascertained from a screening instrument on the PDHA, and provider determination of medical readiness was abstracted from the PHA. Multivariable logistic regression assessed the association between probable TBI and 'not medically ready' (NMR) service member disposition while adjusting for covariates. Overall, 1.8% of the study population screened positive for TBI, and individuals with TBI had a significantly higher prevalence of NMR disposition (7.8%) than those without (3.7%). After adjusting for all covariates, TBI was associated with higher odds of post-deployment NMR disposition (odds ratio 1.5
95% confidence interval, 1.2-2.0). Deployment-related TBI is associated with medical readiness. Future studies are needed to elucidate the TBI sequelae that may lead to NMR disposition as well as the impact of repeated TBIs. This study identified 54% increased odds of NMR disposition for military personnel with probable TBI following deployment, after adjusting for post-traumatic stress disorder and other covariates.