Introduction: Low back pain (LBP) become one of the major complaints among the worldwide population leading to morbidity increase. LBP affects the patient's productivity and quality of life. Frequent hospital visits among patients due to the unknown cause of LBP. This study aimed to determine the most common causes among LBP patients at Surabaya Hajj General Hospital.
 Methods: This is an observational study with a cross-sectional approach. Patients with complaints of LBP who came to the Physical Medicine and Rehabilitation Installation of Surabaya Hajj General Hospital from May to September 2019 were included in this study.
 Results: This study involved a total of 223 participants. Chronic LBP was reported to occur mostly in the mean age of 58.37 years and female participants. The average BMI in this study fell within the obesity range. The three most common causes of LBP included sacroiliac joint (35.4%), piriformis syndrome (27.3%), and facet joint (23.7), followed by other causes such as myofascial trigger point syndrome, canal stenosis, discogenic, and radiculopathy. 
 Conclusion: The most common causes of LBP patients at Haji General Hospital are sacroiliac joint, piriformis syndrome, and facet joint. It is important for the physician to determine the cause of LBP to treat the patient appropriately.