Objectives: To compare the efficacy and safety between leucocyte-rich platelet-rich plasma (LR-PRP) and corticosteroid in fluoroscopically guided caudal epidural injection for patients with complex chronic lumbar spinal pain. Study Design: A prospective randomized controlled doubleblinded study. Methods: Fifty eligible patients with complex chronic degenerative spinal pain were randomly assigned with a 1:1 allocation ratio to receive caudal epidural injection of corticosteroid (triamcinolone acetonide, 60 mg) or LR-PRP (isolated from 60 mL autologous blood) under fluoroscopic guidance. Levels of low back pain, quality of life, and complications (or adverse effects) were evaluated at 1, 3, and 6 months after treatment. Pain levels and quality of life were assessed using the VAS and Short Form 36-Item Health Survey (SF-36), respectively. Results: No significant difference was shown at baseline between the 2 groups. Compared with the pretreatment values, there were significant reductions in the VAS score in both groups. A significantly lower VAS score at 1-month follow-up was detected in patients who received corticosteroid injection. However, the scores were lower in the LR-PRP group at 3-and 6-month follow-up. SF-36 responses at 6 months showed significant improvement in all domains in the LR-PRP group. There were no complications or adverse effects related to treatment at 6-month follow-up in either group. Conclusions: Both autologous LR-PRP and corticosteroid for caudal epidural injections under fluoroscopic guidance are equally safe and therapeutically effective in patients with complex chronic lumbar spinal pain. However, LR-PRP is superior to corticosteroid for a longer pain-relieving effect and improvement in quality of life. &