The objective of this study was to evaluate the efficacy of transcutaneous electrical neurostimulation portable device in patients with chronic nociceptive and neuropathic low back pain. Twenty-four patients with nociceptive and neuropathic lumbar pain were prospectively assigned to apply the active device at the lower back twice daily for 30- min, during 14 days in the morning and at night. Efficacy was evaluated by: 1) pretreatment and post treatment VAS pain scores, 2) type of pain (nociceptive or neuropathic), 3) capacity of performing routine physical activities, 4) quality of sleep, and 5) daily analgesic rescue medication consumption. Nociceptive pain improved (p<0.05) whilst neuropathic pain was maintained (p>0.05). The device decreased pain VAS by day-5th (p<0.05) up to day-14th (p<0.02). Rescue analgesics decreased (p<0.05) and quality of sleep improved (p<0.05). Prior to device, patients referred 2(1-2) (mean (25%-75%)) arousals during night compared to none on day-5th forward (p<0.05). 17 patients classified as improved capacity during the first 3-hours in the morning (p<0.05). There were no adverse effects. The device did not improve neuropathic pain while improved nociceptive pain, decreased the number of rescue analgesics, resulted in better sleep pattern, and enriched physical function in the morning.