AIM: This study aimed to investigate the association between blood fatty acid fractions and posttraumatic stress disorder (PTSD) judgment in individuals who have experienced physical trauma. METHODS: Patients admitted to the emergency department for trauma, excluding those with brain damage or serious psychiatric disorders, were enrolled. Blood samples were collected on admission, and PTSD symptoms were assessed using a questionnaire 1 and 3 months after the injury. Multiple regression analysis was used to evaluate the association between fatty acids and Posttraumatic Diagnostic Scale severity scores, adjusting for age, sex, the Childhood Trauma Questionnaire (CTQ), and the use of psychotropic medications. RESULTS: A significant association was observed between certain fatty acids and PTSD judgment. Mann-Whitney U test results revealed that arachidonic acid was associated with PTSD judgment at 1 month and palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, eicosenoic acid, and eicosadiene acid with PTSD judgment at 3 months. Multiple regression analysis revealed that stearic acid, linoleic acid, arachidic acid, docosatetraenoic acid, lignoceric acid, docosahexaenoic acid, and total omega-6 fatty acids (ω6) were associated with PTSD judgment after 1 month after trauma. In contrast, only linoleic acid and total ω6 were associated with PTSD judgment 3 months after trauma. CONCLUSIONS: This study is the first to enroll patients with general physical trauma and examine the relationship between fatty acids and PTSD. The findings suggest a potential relationship between blood fatty acid fractions and the development of PTSD symptoms in individuals who have experienced physical trauma. However, further research is needed to confirm and expand on these findings.