The protocol titled "Effect of Therapeutic Exercise, Educational booklet and Vitamin D3 Supplement for the Management of Chronic Mechanical Low Back Pain" is authored by Muhammad Shahidul Islam, Ph. D. student at the Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore-7408, Bangladesh. This is a part of his Ph. D. thesis titled “Therapeutic Exercise, Educational booklet and Vitamin D3 Supplement for the Management of Chronic Mechanical Low Back Pain” under the supervision of Dr. Md. Ashrafuzzaman Zahid, Ph. D., Associate Professor, Department of Nutrition and Food Technology, Jashore University of Science and Technology, Jashore-7408, Bangladesh. He is co-supervised by Professor Dr. Md. Sohrab Hossain, Ph. D., Professor, Department of Physiotherapy, Bangladesh Health Professions Institute (BHPI), CRP, Savar, Dhaka-1343, Bangladesh.