Sacroiliitis is a condition that affects the joint connecting the sacrum to the ilium. It may cause pain in the lower back, pelvis, and buttock region, with the possibility of pain radiating to the lower limb. The inflammation may occur on one side or both sides, and its severity varies depending on the underlying cause and associated medical condition. The importance of this condition lies in the fact that its symptoms may resemble those of several disorders of the lumbar spine, pelvis, and hip joint. Therefore, an accurate clinical assessment is an essential step toward establishing an appropriate diagnosis. Sacroiliitis is defined as inflammation or irritation of the sacroiliac joint, which connects the spine to the pelvis and contributes to transferring loads between the trunk and the lower limbs. Sacroiliitis may result from inflammatory, mechanical, or traumatic causes. Common causes include axial inflammatory diseases such as ankylosing spondylitis, injuries or repetitive strain, pregnancy-related changes due to increased load and hormonal changes, as well as certain movement disorders, uneven pelvic loading, infections, and systemic diseases. Clinical symptoms commonly present as pain in the lower back or buttock region, and the pain may be more pronounced on one side. Pain may worsen with prolonged standing, climbing stairs, running, walking long distances, or changing position. Some patients may also experience morning stiffness or nighttime pain, particularly when the underlying cause is related to an inflammatory condition. Diagnosis is based on the patient's medical history and clinical examination, supported by a series of specific sacroiliac joint provocation tests. Imaging techniques such as X-rays or magnetic resonance imaging (MRI) may be used when necessary, particularly when inflammatory changes or structural injury are suspected. Laboratory tests may also be requested when an inflammatory or systemic disease is suspected. It is important to differentiate sacroiliitis from other causes of lower back pain, such as lumbar spine disorders and hip joint problems. Treatment of sacroiliitis is determined according to the underlying cause, severity of symptoms, and the patient's functional status. Conservative management usually includes health education, activity modification, pain management, and physical therapy. Physical therapy focuses on assessing pain, range of motion, muscle strength, motor control, and functional problems, followed by designing an individualized treatment program. This program may include therapeutic exercises, strengthening exercises for the core, pelvic, and hip muscles, flexibility exercises, functional movement training, and improvement of movement and loading patterns. The treatment program should gradually increase exercise intensity according to the patient's tolerance, while avoiding activities or techniques that cause a significant increase in pain and monitoring the patient's response to treatment. Physical therapy represents an important component of rehabilitation for appropriate patients, as it aims to improve motor function, reduce pain, and support the ability to perform daily activities. Health education also helps improve the patient's adherence to the treatment program by teaching appropriate postures and movements and avoiding unsuitable loads. Maintaining appropriate physical activity, strengthening the core and pelvic muscles, and maintaining proper movement mechanics can contribute to reducing functional problems associated with the pelvic region. Inflammatory or severe cases require specialized medical evaluation and may require medication or additional interventions depending on the underlying cause. In conclusion, sacroiliitis is an important disorder affecting the pelvic and lower back regions. Its causes may be mechanical, inflammatory, or associated with other medical conditions. Accurate diagnosis helps determine the appropriate treatment and prevents confusion with other causes of lower back pain. Physical therapy plays an important role in appropriate cases through therapeutic exercises, improvement of movement and function, and health education, while the rehabilitation plan should be based on the underlying cause and the individual condition of each patient. Al-Mustaqbal University The First University in Iraq