To investigate lumbar spinal lesions in rheumatoid arthritis (RA), we examined the lumbar spine of patients with RA radiologically. Forty-six RA patients suffering from low back pain were included (7 males and 39 females). Some abnormal findings were obtained in 42 patients (91%). There were disc narrowing in 28 patients (61%), bone spur in 21 patients (46%), erosion of the terminal plate of the vertebra in 19 patients (41%), compression fracture of the vertebra in 17 patients (37%), spondylolishthesis in 13 patients (28%), and destruction of the vertebra in 3 patients (7%). These findings suggest that the low back pain in patients with RA are caused by age-related degeneration and/or inflammatory changes associated with RA.