Post-traumatic stress disorder (PTSD) is associated with an increased risk for physical illnesses and early mortality. However, we do not know if it also increases the risk for adverse outcomes of coronavirus disease 2019 (COVID-19). In this retrospective cohort study, we examined associations of PTSD and other psychiatric disorders with risk for hospitalization and death in the 60 days following a COVID-19 infection in 228,367 U.S. Department of Veteran Affairs (VA) patients who tested positive for COVID-19 between February 2020 and August 2021 (age m = 60.6, 89.5% male). Generalized linear models estimated associations of PTSD and other psychiatric disorders with outcomes following a positive SARS-CoV-2 test, adjusting for socio-demographic, medical, and behavioral factors. Among 228,367 VA patients, 25.6% had PTSD, and 28.2% had a psychiatric disorder other than PTSD. In the 60 days following a positive COVID-19 test, 15% of patients were hospitalized, and 6% died. Patients with PTSD had an increased risk for both hospitalization (adjusted relative risk, ARR = 1.18, 95% CI 1.15-1.21) and death (ARR = 1.13, 95% CI 1.08-1.19) relative to those with no psychiatric disorders, adjusting for socio-demographics. Estimates remained significant when models were additionally adjusted for medical comorbidities and smoking. Patients with other psychiatric disorders also had an increased risk of adverse COVID-19 outcomes, with larger effect sizes than PTSD in older (≥65 years) but not younger patients. In this large-scale study of VA patients, individuals with PTSD, and other psychiatric disorders, had heightened vulnerability to severe adverse outcomes of COVID-19; thus, individuals with PTSD should also be considered at higher risk for severe COVID-19 outcomes, and potentially prioritized for vaccination, screening, and early treatment intervention for COVID-19.