The purpose of this study was to assess the outcome of peri-radicular infiltration for radicular pain in patients with spinal stenosis and lumbar disc herniation (LDH). Patients with spinal stenosis ( n=62) or LDH ( n=55) who met our criteria received fluoroscopically guided peri-radicular infiltration of local anaesthetic and steroid at the site of documented pathology. All the patients were followed-up at 3 months. There was a statistically significant difference in the functional outcome between the spinal stenosis group and the LDH group. The mean change in the Oswestry disability index (ODI) score for the spinal stenosis group was 5.5% compared to 12% for the LDH group. The spinal stenosis group had a mean change in visual analogue scales (VAS) of 1.2 compared to 2 for the LDH group. The higher the modified somatic perception score, modified zung depression and age at injection, the less favourable the outcome. There was a significantly better response to peri-radicular infiltration for radicular pain in patients with LDH than the spinal stenosis. Our findings help us to provide a better information for future patients. We do not know if this is a treatment effect or natural history of the pathology, as this is a cohort study and not a randomised controlled trial.