Background and Objectives: Chronic neck pain and low back pain are common conditions in high-income countries leading to social and medical problems such as invalidity and decreased quality of life. The aim of this study was to investigate the effect of supra-threshold electrotherapy on pain level, subjective feeling of disability, and spinal mobility in patients with chronic pain in the spinal cord.Materials and Methods: 11 men and 24 women with a mean age of 49 years were randomly divided into three groups: group 1, “therapy”: supra-threshold electrotherapy was applied on the whole back after electrical calibration; group 2, “control”: electrical calibration without successive electrotherapy; group 3, “control of control”: no stimulation. Sessions were performed once a week and six times in total, each lasting 30 min. The numeric pain rating scale (NRS), cervical and lumbar range of motion (ROM), as well as disability in daily live were investigated before and after the sessions using questionnaires (Neck Disability Index, Roland Morris Questionnaire, Short-form Mc Gill Pain Questionnaire (SF-MPQ)).Results: Spinal mobility improved significantly in the lumbar anteflexion (baseline mean, 20.34 ± SD 1.46; post session mean, 21.43 ± SD 1.95;p= 0.003) and retroflexion (baseline mean, 13.68 ± SD 1.46; post session mean, 12.05 ± SD 1.37;p= 0.006) in the group receiving electrotherapy. Pain levels measured by the NRS and disability-questionnaire scores did not differ significantly before and after treatment in any of the groups.Conclusions: Our data indicate that regular supra-threshold electrotherapy for six times has a positive effect on lumbar flexibility in chronic neck pain and low back pain patients, whereas pain sensation or subjective feeling of disability remained unchanged.