BACKGROUND: Degenerative lumbar spinal stenosis is one of the most common causes of chronic lower back pain and radiculopathy. Spinal stenosis is anatomically classified as central and lateral spinal canal stenosis. Many treatment modalities and techniques, including surgery and epidural injection, have been used to manage the pain. However, the effect of hypertonic saline injection via the transforaminal approach has not yet been studied. OBJECTIVES: The aim of this study is to determine the effect of adding hypertonic saline to conventional transforaminal epidural steroid injections (TFEI) to provide pain relief for chronic radiculopathy patients secondary to lateral canal spinal stenosis. STUDY DESIGN: A double-blind, randomized, active-control trial. SETTING: An interventional pain management practice in a hospital, Republic of Korea. METHODS: Two groups: the hypertonic group received hypertonic saline combined with triamcinolone and the control group received normal saline combined with triamcinolone. A total of 68 patients were randomly allocated into either 2 groups by a computer-generated randomization program. Twenty-seven patients in the hypertonic group and 26 patients in the control group were assessed. A total of 53 patients were included in this analysis. Outcome measures were taken at baseline, one, 2, 3, 4, and 6 months post-procedure. The primary outcome measures included the numerical rating scale (NRS) and the proportion of substantial responders. The secondary outcome measures included the Oswestry disability index (ODI), the proportion of substantial and moderate responders, and patient satisfaction. RESULTS: Transforaminal epidural injection of steroids, with or without the addition of 10% hypertonic saline, was effective and provided significant pain relief with the improvement of functional outcome within 4 months. The addition of hypertonic saline was superior in efficacy compared with conventional TFEI at 3 months follow-up. The differences in the absolute pain scores did not demonstrate statistical significance between the 2 groups. The reduction in pain intensity from the baseline was greater in the hypertonic group and demonstrated higher rates of satisfaction. The use of hypertonic saline also extended the duration of significant pain relief to 6 months compared with baseline. LIMITATIONS: The lack of placebo group and small sample size. CONCLUSION: Superior short-term pain relieving efficacy, but limited long-term effects of hypertonic saline, when added to TFEIs.