ABSTRACT Chronic low back pain (CLBP) is a common musculoskeletal disorder which is a cause for functional disability among the working population with a negative psychological impact. Treatment for CLBP may be drugs and physical therapy. Infrared radiation therapy (IRR) is a physical therapy modality used in CLBP that has not been completely evaluated to determine its efficacy. The objective of this study was to determine the efficacy of IRR for pain relief in CLBP. 48 subjects participate...