We report a patient with a stress fracture in the sacrum. This may be a cause of hip or back pain. In contrast to typically bilateral insufficiency fractures, fatigue fractures are usually unilateral and the appearances are not diagnostic on scintigraphy. As the plain film findings may be subtle and overlooked, computed tomography is more specific in delineating a sclerotic vertical fracture parallel to the sacroiliac joint. Recognition of the characteristic radiographic pattern in sacral fatigue fractures can avoid incorrect diagnosis and unnecessary tests or treatment.