Osteitis condensans ilii (OCI) is a benign pathology causing chronic back and hip pain. Although the definitive cause is uncertain, mechanical stress is a significant factor in the development of the disease. Bilateral involvement of the sacroiliac joint is typical. We describe a case of unilateral OCI with unilateral sclerosis observed at radiography in a 34-year-old patient presenting with chronic back and hip pain, together with a review of the literature.