The management of low back pain (LBP) encompasses a diverse range of possible interventions including drug therapy, surgery, exercise, patient education, physiotherapy, cognitive-behavioral therapy and various other non-pharmacological therapies. Acute and chronic LBP warrant separate consideration as they may respond differently to the same interventions. Transcutaneous electrical nerve stimulation (TENS) is widely used as a therapeutic adjunct in the management of low back pain. It is relatively safe, non-invasive and easy to use modality that makes it an attractive treatment option. For more than four decades, TENS has been applied in the treatment of acute and chronic pain syndromes. Hence there is still uncertainty about the most effective therapeutic approach in chronic non-specific low back pain. Methods: This randomized controlled clinical trial was conducted in the department of Physical Medicine and Rehabilitation, Chatto gram from 13/01/2019 to 13/06//2019. The aim of the study was to evaluate the effects of Transcutaneous Electrical Nerve Stimulation on Chronic Non-specific Low Back Pain Patients. 120 patients with chronic low back pain were treated according to inclusion & exclusion criteria. Patients were equally distributed in three groups. Group-A patients (n=40) treated with NSAID+ADL, and Group-B patients (n=40) treated with NSAID+ADL+TENS and Group-C patients (n=40) treated with NSAID+ ADL+ Back extension exercise. Written informed consent was obtained from all patients. Data were calculated and analyzed by computer based software SPSS (Statistical Package for social Science) windows 16.0 version. Main Outcome Measure (S): Age, Sex, Occupational status, Socio-economic status, Subjective pain intensity score, Visual Analogue Scale, Tenderness index, Disability due to pain, Spinal mobility index, Oswestry disability Index. Results: The mean age was found 41.82±11.95 years in group A and 42.7±12.52 years in group B and 40.52±13.40 in group C.........