BACKGROUND OF THE STUDY:Low back pain is one of the most common health problem and 80 percent of the people experiences low back pain in their lifetime. Majority of low back pain is due to the muscle imbalance. Muscle imbalance occurs due to shortened or lengthened in structure and it leads to injury which causes changes in motor programming. OBJECTIVE: To compare the effects of Muscl Energy Technique, positional release technique and conventional therapy on improving pain, range of motion and functional ability in patients with mechanical low back pain. SUBJECTS AND METHODS:Twenty four patients of complaining of mechanical low back pain participated in the study. Patients were randomly allocated using computer generator software into three groups: group A which recieved Muscle energy technique, group B which recieved Positional release technique and group C which recieved conventional therapy. Treatment sessions were given three times per week for three weeks. Patients were assessed before and after treatment using Numerical Pain Rating Scale(NPRS), Modified Oswestry Disability Index(MODI), and Modified Schober's Test to assess pain severity, functional ability and range of motion of lumbar spine respectively. RESULTS: Based on this statistical analysis, Group A showed better Statistical significance in NPRS, MODI and ROM mean value as compared to Group B and C. Hence alternate hypothesis is accepted and null hypothesis is rejected. This we conclude that Muscle energy technique is more beneficial compared to Positional release technique and conventional therapy. Conclusion: Muscle energy technique and conventional therapy groups shows significant improvement on pain and lumbar extension range of motion compared to Positional release technique, whereas there was no significant difference in MODI on muscle energy technique, positional release technique and conventional therapy