BACKGROUND Percutaneous endoscopic lumbar discectomy (PELD) has gained popularity as a minimally invasive surgery for treating lumbar disc herniation. However, there is limited research focusing on the reoperation rate and its associated factors. This study aims to investigate the rate of reoperation and identify the causes and risk factors for reoperation after PELD. MATERIAL AND METHODS We conducted a retrospective analysis of patients who underwent PELD (interlaminar and transforaminal approaches) at our hospital from November 2016 to May 2020. A matched case-control design was employed to identify relevant risk factors for reoperation, with a matching ratio of 1:3. Clinical characteristics and radiological parameters were compared, and univariate analysis was performed using independent samples t-test and chi-squared test. RESULTS Among the 435 patients included in the study, the reoperation rate for those with a minimum 2-year follow-up was 6.2% (27/435). The causes of reoperation and their respective rates were as follows: recurrence of lumbar disc herniation (3.2%, 14/435), incomplete decompression (1.8%, 8/435), persistent low back pain (0.7%, 3/435), and postoperative infection (0.5%, 2/435). Univariate analysis revealed that age (P=0.015), Pfirrmann grade IV-V (P=0.017), and lack of active straight leg raise exercises (P=0.026) were significantly associated with reoperation. Multiple logistic regression analysis indicated that age (P=0.001), Pfirrmann grade IV-V (P=0.033), and lack of active straight leg raise exercises postoperatively (P=0.003) were independent risk factors for reoperation after PELD. CONCLUSIONS The primary cause of reoperation in lumbar disc herniation patients after PELD was recurrence of the herniation. Additionally, severe disc degeneration, older age, and lack of active straight leg raise exercises were identified as significant risk factors associated with an increased reoperation rate.