The purpose of the study was to investigate whether experiencing fear of dying after acute coronary syndrome predicts later posttraumatic stress symptoms. We enrolled 90 patients hospitalized with main diagnosis of acute coronary syndrome and assessed baseline characteristics. One month after discharge, we collected the Posttraumatic Stress Scale. A total of 24 patients (26.7%) developed posttraumatic stress symptoms 1 month after the acute coronary syndrome event. Patients with posttraumatic stress symptoms reported significantly greater fear of dying, helplessness, avoidance-focused coping, and severe anxiety. In our prospective study, fear of dying was associated with occurrence of posttraumatic stress symptoms in patients hospitalized with acute coronary syndrome.