Objective: Studies investigating the relationship between posttraumatic stress disorder (PTSD) that is chronic psychiatric disorder and C-reactive protein (CRP) have inconsistent results. However, to our knowledge, there is no study investigating the effect of PTSD-related trauma type on plasma CRP levels. This study was planned to determine the effect of PTSD and PTSD-related trauma type on plasma CRP levels. Methods: The sample of this cross-sectional study consisted of 73 PTSD patients and 69 healthy control subjects. After proper blood collection, Clinician-administered PTSD Scale (CAPS) was administered by the researchers and Sociodemographic Data Form, Beck Depression Inventory (BDI) and Dissociative Experiences Scale (DES) were requested. Results: CRP, BDI and DES scores of PTSD patients were statistically higher than healthy controls. There were statistically signifi-cant differences between plasma CRP level, CAPS and DES scores according to different trauma types. In the comparison of bilateral groups, plasma CRP levels of occupational accident-induced PTSD patients were statis-tically higher than patients with PTSD due to other types of trauma. Conclusion: As a result, there were differences in plasma CRP levels between PTSD patients and healthy control group and plasma CRP levels were found to vary with the type of trauma associated with PTSD. [Anadolu Psikiyatri Derg 2019; 20(6.000): 573-580]