Background: Posttraumatic stress disorder (PTSD) is a psychiatric syndrome associated with high levels of sympathetic activation of the autonomic nervous system. Individuals diagnosed with PTSD have a high propensity for electrocardiogram (ECG) abnormalities, atrioventricular conductive defects, and cerebrovascular incidents. Purpose: The aim of this study was to investigate ECG abnormalities in post-war PTSD patients. Method: This pilot study compared patients diagnosed with chronic post-war PTSD (n = 30) to patients diagnosed with major depressive disorder (MDD; n = 24) and healthy controls (n = 20). Following the completion of the Structured Clinical Interview for the DSM (SCID), participants were assessed with a standard 12-lead ECG. Results: ECG abnormalities were observed in 66.7% of PTSD patients and 70.8% of MDD patients. In contrast, only 28.6% of the healthy control group showed ECG abnormalities. Multivariate logistic regression was used to adjust for participants' sex, smoking rate, education level, disease duration, and marital status. The results indicated that PTSD and MDD patients were more likely to have ECG abnormalities than the normal population (odds ratio for PTSD = 12.7, 95% confidence interval 1.9-83.9; and odds ratio for MDD = 14.9, 95% confidence interval 1.3-170.5). Conclusion: PTSD and MDD patients showed elevated rates of ECG abnormalities compared to healthy controls. These findings have important implications for the medical treatment of PTSD and MDD given that both of these patient groups appear to be at increased risk of cardiovascular disorder. © 2011 International Society of Behavioral Medicine.