Background: Pain is the most common complaint after inguinal hernia surgery. The present study was undertaken to evaluate the significance of various perioperative clinical factors on the severity of postoperative pain following endoscopic totally extraperitoneal (TEP) inguinal hernioplasty.Methods: Between November 1999 and December 2002, 509 patients who underwent unilateral (n = 389) and bilateral (n = 120) TEP were recruited for this study. There were 491 men and 18 women. Severity of postoperative pain at rest and on coughing was assessed by a linear analogue pain score (scale, 0–10) on a daily basis after operation. Univariate and multivariate analyses were performed to identify the significant independent factors affecting pain. Results: By univariate analysis, pain scores at rest were significantly higher in young (≤65 years) female patients, as well as patients who underwent unilateral and day case TEP. Clinical factors associated with a significantly higher pain score on coughing included mesh fixation by stapling, female sex, and age (≤65 years). Other factors, including unilateral vs bilateral TEP, seroma formation, direct vs indirect hernia, primary vs recurrent hernia, and operative time, had no impact on postoperative pain. On multiple regression analysis, age and sex were found to be independent predictive factors for mean daily pain score at rest. Independent factors influencing mean pain score on coughing included age, sex, and prosthetic stapling. Conclusions: Patient age and sex are the most significant factors determining the degree of pain after TEP. Analgesic therapy should therefore be adjusted in accordance with the age of the patient. With regard to operative factors, avoidance of prosthetic stapling might help to reduce the severity of pain on coughing.