Epidural steroid injection is commonly used in treating radicular pain secondary to lumbar disc prolapse which is a common clinical condition. Two techniques were suggested to deliver the steroids: Interlaminar and Transforaminal approaches. From June 2013 to March 2014 we performed in Cairo University hospitals a prospective study on 40 patients, aged between 19 and 55 years. All the patients had low back pain and lower limb radiculopathy secondary to a single level lumbar disc prolapse. The pupose of this study is to compare between both techniques regarding the improvement of back pain, leg pain and functional outcome on the immediate & short term. So on admission, the patients were evaluated using VAS score for back pain, VAS score for Leg pain and the Oswestry Disability Index for functional capacity. They were followed up in a period of 11 to 13 weeks with a mean of 12 weeks and clinical and functional outcomes were assessed using the same tools for evaluation. This study found that back pain, leg pain and the functional outcome improved in both, transforaminal and interlaminar group on the immediate and short term, but only the improvement in leg pain and the functional status showed statistical significance between both groups. During or study there was no serious complications. We found by the end of the study that the epidural steroid injection is a safe procedure in general but the transforaminal approach gives better results than the interlaminar approach in relieving radicular pain and improving the functional outcome.