OBJECTIVE: The aim of this study was to compare the therapeutic and functional values between the L5-S1 transforaminal epidural steroid injection (TFESI) and L4-5 TFESI in patients with L5 radiculopathy. METHOD: Among 30 patients with unilateral herniated nucleus pulposus (HNP) and L5 radiculopathy, 15 patients received L5-S1 TFESI and 15 patients received L4-5 TFESI. All patients were checked visual analogue scale (VAS) and functional score before injection, after 1 day, 2 weeks and 4 weeks. RESULTS: The VAS of before injection, after 1 day, 2 weeks and 4 weeks were 6.6, 4.0, 3.0, and 2.8 in L5-S1 TFESI, 6.2, 3.9, 2.7, and 2.6 in L4-5 TFESI, respectively. The functional score of before injection, after 1 day, 2 weeks and 4 weeks were 1.8, 2.3, 2.6, and 3.0 in L5-S1 TFESI, 1.6, 2.2, 2.5, and 2.8 in L4-5 TFESI, respectively. There was no statistical difference between the groups (p>0.05). CONCLUSION: This study suggested that either L5-S1 TFESI or L4-5 TFESI could be a valuable treatment of L5 radicular pain.