Aim:This study aimed to evaluate the effects of administering pethidine (also known as meperidine), a long-acting narcotic analgesic, via the caudal epidural route at the conclusion of posterior lumbar instrumentation (PLI) surgery on postoperative pain control and early mobilization of patients. Material and Methods:Cases included in this prospective study (n=48) were randomly divided into two groups, ensuring similar gender and age distributions and uniformity regarding the lumbar pathologies requiring surgery. In the first group, 20 ml of sodium chloride (0.09%) solution containing pethidine chloride (0.5 mg/kg) was administered via a caudal epidural block before the patients awakened from anesthesia. The control group consisted of cases where the caudal epidural block was not performed using pethidine or any other pharmaceutical/pharmacological agent. Visual Analog Scale (VAS) pain assessments were performed in both groups at preoperative, postoperative and 24, 48 and 72 hours after awakening and recovery. Additionally, oral feeding at the sixth postoperative hour and mobilization at the eighth postoperative hour were evaluated for all cases. Results:VAS scores of cases administered pethidine via a caudal block were found to be significantly lower at all measurement times compared to those without a caudal epidural block (p<0.05). It was revealed that the need for analgesic medication in terms of both dosage and duration was lower in the pethidine group during the postoperative period. Both groups began oral feeding at the sixth postoperative hour. However, it was observed that cases in the pethidine group were mobilized with ease at the eighth postoperative hour, whereas those without a caudal epidural block with pethidine could only mobilize as early as the 24th postoperative hour. Conclusion:These results suggest that administering pethidine via a caudal epidural block before awakening at the conclusion of PLI surgery may provide benefits in both postoperative pain control and early mobilization.