Abstract: Background: Post-traumatic stress disorder (PTSD) significantly impacts US Veterans' well-being by potentially exacerbating health-related social needs (HRSN). This study investigated short- and long-term associations between PTSD diagnosis and nine HRSN indicators. Methods: Utilizing national Veterans Health Administration (VHA) electronic health record (EHR) data, we employed dual designs. A cross-sectional analysis included 62,298 Veterans (PTSD diagnosed in fiscal year [FY] 2012 vs. non-PTSD), matched on key demographic and comorbidity factors. A retrospective cohort followed 11,758 propensity-matched Veterans (no baseline HRSN at FY2012) from FY2013-FY2023. Outcomes were nine HRSN indicators identified via codes and natural language processing in EHRs. Results: Cross-sectionally (N = 62,298), PTSD was linked to higher prevalent HRSN odds at baseline, including violence (adjusted odds ratio [aOR] = 3.98; 95% CI: 3.77-4.20), social problems (aOR = 2.87; 95% CI: 2.73-3.01), and legal issues (aOR = 1.75; 95% CI: 1.64-1.87). In the cohort study (N = 11,758), baseline PTSD strongly predicted incident HRSN across all nine indicators in the first year (e.g., violence: adjusted hazard ratio [aHR] = 3.05; 95% CI: 2.68-3.47). Though strongest initially, these associations attenuated but remained significant up to 10 years post-diagnosis. Conclusions: US Veterans diagnosed with PTSD face substantially elevated short- and long-term risks for diverse HRSN, including critical social, financial, housing, and legal problems. These persistent vulnerabilities demand integrated healthcare with routine screening, monitoring, and targeted interventions to address complex needs and improve Veteran well-being.