Sacral insufficiency fractures (SIF) that usually present as nonspecific pelvic or low back pain are often overlooked in the elderly. In a retrospective study conducted in a department of internal medicine, 16 patients with SIF were identified during a 6-year period. All patients were elderly women (mean age of 81 years) who presented with low back or pelvic pain. Radicular pain in the lower limb was common. Ten patients were bedridden. All 16 patients were osteopenic. Plain radiographs of the pelvis were nondiagnostic in 11 patients. Radionuclide bone scan showed a typical H-shaped pattern of increased uptake in 11 patients, and computed tomographic scan confirmed SIF (9/9 patients). With bed rest and analgesics, outcome was favorable in all patients. This study confirms the nonspecific presentation of SIF and the need to maintain a high index of clinical suspicion to make a prompt diagnosis and avoid unnecessary and sometimes invasive procedures.