PURPOSE: Nerve identification during open inguinal hernia herniorrhaphy has been suggested as one of the factors that may reduce the risk of development of persistent postherniorrhaphy pain. In this prospective study, we evaluated whether intraoperative inguinal nerve identification influenced the risk of development of persistent postherniorrhaphy pain, sensory dysfunction in the groin and functional ability score after open hernia repair. METHODS: A total of 244 men with a primary inguinal hernia underwent open Lichtenstein repair in a high-volume hernia surgery centre, where information on inguinal nerve identification was registered during operation. Before the operation and 6 months postoperatively, functional pain-related impairment was assessed with Activities Assessment Scale and pain intensity scores with Numeric Rating Scale (NRS 0-10). Quantitative sensory testing in the groin was performed before operation and 6 months postoperatively, in order to investigate intraoperative inguinal nerve damage. RESULTS: The intraoperative nerve identification rates for the iliohypogastric, ilioinguinal and genitofemoral nerves were 94.7, 97.5 and 21.3 %, respectively. Thirty-nine patients (16.0 %) had substantial pain-related functional impairment at 6 months follow-up. There was no difference in risk of development of substantial pain-related functional impairment in patients with identification compared with non-identification of the iliohypogastric nerve (P = 1.0), the ilioinguinal nerve (P = 0.59), the genitofemoral nerve (P = 0.40) or all nerves (P = 0.52). There were no differences in regard to sensory loss in the groin area or in regard to improvement in functional outcome following surgery, between patients with and without nerve identification. CONCLUSIONS: Although intraoperative inguinal nerve identification should be aimed at, other factors may contribute to the risk of nerve damage and persistent pain after open groin hernia repair.