Objective: Posttraumatic stress disorder (PTSD) has been observed in cardiac patients, but little is known about PTSD in implantable cardioverter defibrillator (ICD) patients. We examined the prevalence and predictors (clinical variables, personality, and anxiety) of PTSD in ICD patients. Method: Three hundred ninety-five ICD patients (20.1% female; mean age = 62.8 ± 10.3 years) from two Dutch referral hospitals completed the 14-item Type D scale (DS14) and the State–Trait Anxiety Inventory to assess Type D (distressed) personality (high negative affect with social inhibition) and anxiety (on the State Anxiety Inventory) at the time of implantation. Logistic regression analysis was performed to identify independent predictors of PTSD at 18 months postimplantation. Results: At 18 months postimplantation, 30 patients (7.6%) qualified for a PTSD diagnosis. Of these patients, 55% (n = 16) had a Type D personality, 83% (n = 25) experienced anxiety at baseline, and 24% (n = 7) had experienced shocks during follow-up. Both Type D personality (odds ratio [OR] = 3.5) and baseline anxiety (OR = 4.3) were significant predictors of posttraumatic stress at 18 months postimplantation, independent of shocks and other clinical and demographic covariates. Shocks were not significantly associated with PTSD. Conclusion: A significant group of ICD patients is at risk of posttraumatic stress 18 months postimplantation, especially Type D patients and patients with increased levels of baseline anxiety. Identification of patients with Type D personality and anxiety at the time of implantation may be warranted to prevent PTSD in ICD patients.