Background: Psychological symptoms frequently accompany severe injuries of the upper extremities and are described to influence functional outcome. As yet, little knowledge is available about the occurrence of posttraumatic psychological stress and the predictive characteristics of peripheral nerve injuries of the upper extremity for such psychological symptoms. In this prospective study, the incidence of different aspects of early posttraumatic stress in patients with peripheral nerve injury of the forearm is studied as well as the risk factors for the occurrence of early psychological stress. Methods: In a prospective study design, patients with a median, ulnar or combined median-ulnar nerve injury were monitored for posttraumatic psychological stress symptoms with the Impact of Event Scale (IES) questionnaire up to 3 months postoperatively. Results: Psychological stress within the first month after surgery occurred in 91.8% of the population (IES mean=22.0, standard deviation (SD)=17.3). Three months postoperatively, 83.3% (IES mean=13.3, SD=14.1) experienced psychological stress. One month postoperatively 24.6% and 3 months postoperatively 13.3% of the patients had IES scores indicating for the need for psychological treatment. Female gender, adult age and combined nerve injuries were related to the occurrence of psychological stress symptoms 1 month postoperatively. Conclusions: In the majority of these patients, peripheral nerve injury of the forearm is accompanied by early posttraumatic psychological stress, especially in female adults who suffered from combined nerve injuries. (C) 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.