This study sought to visualize spinal-cord stimulation activity by infra-red thermography in humans suffering from chronic lumbosciatic pain. All the patients had previously undergone neurosurgery for a herniated intervertebral disc. Temperature changes were evaluated in two defined body areas after starting, stopping, maintaining or not starting the stimulation. In one body area, corresponding to the pain location, the patient experienced stimulation paraesthesia, whereas in the non-painful (second) area no stimulation paraesthesia were present. The patients were studied on four consecutive days with a randomly chosen stimulation pattern. Temperature changes in identical and comparable skin areas were measured and statistically analysed. No statistically significant temperature variation was found between the painful and non-painful areas. These findings do not confirm the idea that spinal cord stimulation induces vasodilation in the affected pain area when stimulation is present. Infra-red thermography is not able to differentiate the stimulated from the non-stimulated areas.