Iliopsoas bursa enlargement, a rare cause of pelvic or inguinal mass, can be identified on computed tomography (CT) either incidentally or during clinical examination of a groin mass. When CT examination is equivocal, hip arthrography can establish the diagnosis. Iliopsoas bursa enlargement is frequently associated with preexisting hip arthrosis. In three cases of iliopsoas bursa enlargement, two had preexisting arthritis. A third patient showed no roentgenographic sign of hip disease. Iliopsoas bursa enlargement may be more common than previously reported and should be considered in patients with unexplained hip pain who demonstrate a soft tissue mass in the region of the iliopsoas bursa.