Aim There is a discrepancy between the high frequency of chronic post-operative pain reported in questionnaire-based studies after groin hernia surgery and the clinical experience of many surgeons in which it is infrequent that patients return after surgery because of chronic post-operative pain. This is supported by the Swedish Hernia Registry, where the proportion of patients who are re-operated for chronic post-operative pain is 0.02-0.03% for open methods and less than 0,01% for laparo-endoscopic methods. The aim of this study is to find the incidence of non-surgical causes of chronic groin pain and other patient-reported outcomes after inguinal hernia surgery. Material and Methods Prospective cohort observation study of patients evaluated for suspected inguinal hernia-related symptoms at a hernia clinic in Sweden during 1 year. Patients completed validated pain forms before surgery and 6 and 12 months after surgery. Patients were assessed preoperatively about the possible causes of groin pain according to a checklist. For this purpose, a questionnaire of inguinal hernia-related symptoms was used. Patients with moderate or severe chronic groin pain after surgery were offered to participate in a clinical examination where the pain was evaluated for probable cause according to a checklist. Results 574 patients were included in the study, of which 372 were operated on and answered the post-operative questionnaires. Preliminary results on surgical and non-surgical causes of chronic groin pain after hernioplasty and other patient-reported outcomes will be presented at Hernia 2021 EHS-AHS Joint Congress. Conclusions Proportion of patients with chronic groin pain related to groin hernia surgery and other non-surgical pathologies will be reported.