Background: Low back pain is one of the most common ones of musculoskeletal disorders patients’ complaint, Patients with low back pain have disability interferes with quality of life and work performance and often have negative effects on their activity of daily livings. The aim of the study was to evaluate the effect of lumbar flexion exercise program on pain and disability among patients with chronic low back pain. Research design: Quasi experimental research design was used to conduct the aim of this study. Setting: The study was conducted in the spine and neurosurgery out-patient clinics affiliated to Benha University Hospital, Benha, Egypt. Sample: A purposive sample of (100) adult patients with low back pain were taken from both sexes , their age ranged from 51 to 60 years old during six months . four tools were used; (1) Patients' structured interviewing questionnaire (2) Numeric Pain Rating Scale (3) Oswestry Disability Index(4) Anthropometric Measures Assessment. Results: There were highly statistical differences of patients’ reported practice regarding lumbar flexion exercise, there was positive improvement regarding patients' independency in activities of daily living and also, self-care improved significantly after applying of program. Finally there were statistically significant differences regarding all items of pain assessment between pre, two weeks and four weeks post program implementation. Conclusion: The degree of pain and disability among patients with low back significantly improved post program implementation which reflects that lumbar flexion exercise was effective in reducing pain intensity , disability and had a positive impact on patients' daily activity performance with high statistically significance differences (p= |