Low back pain and gait disturbance began at 6 months of pregnancy in a twenty- eight years old female patient. She could not walk by herself after delivery because of severe pain and limitation of motion on pelvis. Irregular bony destruction on right sacroiliac joint and rotation of pelvis demonstrated on plain radiography. Tuberculosis was confirmed by CT guided needle biop-sy. Back pain developing during pregnancy and after delivery can by overlooked as osteitis condensans ilii or nonspecific back pain. Tuberculous sacroilitis should be suspected for the patient with severe pelvic pain and bony destruction on sacroiliac joint, and with rotation of pelvis after delivery. Early diagnosis and proper treatment by anti-tuberculous medication could obtain satisfactory functional outcome. We have described an unusual case of tuberculous sacroiliitis associated with pregnancy in a 28 years old female patient and her clinical presentation, radiological features and outcome of medical treatment are discussed.