BACKGROUND This retrospective study aimed to investigate the risk factors associated with the recurrence of L5-S1 disc herniation after percutaneous endoscopic transforaminal discectomy (PETD). MATERIAL AND METHODS There were 484 patients L5-S1 disc herniation who underwent PETD who were divided into the recurrence group (n=46) and the non-recurrence group (n=438). Transforaminal endoscopic approaches included modifications of the Yeung endoscopy spine system (YESS) (the intraforaminal intradiscal approach) and the transforaminal endoscopic spine system (TESSYS) (intraforaminal extradiscal approach). Demographic and clinical characteristics and imaging data were analyzed. The two study groups were compared to determine the factors associated with the recurrence of L5-S1 disc herniation. The patients underwent postoperative follow-up for between one and four years. RESULTS At follow-up, 9.504% of patients (46/484) with the recurrence of L5-S1 disc herniation following PETD when compared with the non-recurrence group showed no significant difference for time to return to work, gender, history of diabetes mellitus, trauma, duration of symptoms, smoking and alcohol history, hypertension, location of disc herniation, transverse process length, intervertebral space height, and pelvic incidence angle (P>0.05). However, age, body mass index (BMI), the degree of disc degeneration, sagittal range of motion, lumbar lordosis angle, and sacral slope were significantly associated with the recurrence of L5-S1 disc herniation following PETD (P<0.05). Logistic regression analysis supported these main associations. CONCLUSIONS The recurrence of L5-S1 disc herniation following PETD was significantly associated with increased age and BMI, more severe disc degeneration, increased sagittal range of motion, increased lumbar lordosis, and sacral slope.