About 2% of all bladder calculi occur in women. Their presence necessitates a careful assessment of the cause. Most bladder calculi secondary to female pelvic surgery result from either obstruction or foreign objects. The presence of nonabsorbable suture material in the bladder is a well-known cause of urinary tract infection and stone formation. We present the sonographic findings in a case of a bladder stone forming around nonabsorbable sutures after a Marshall-Marchetti-Krantz operation for stress urinary incontinence.