Bladder exstrophy is a rare congenital condition that occurs in 1 to 30,000 live births. Primary bladder closure is usually performed in the first days of life in conjunction with an iliac osteotomy in order to achieve a more secure bladder closure. We report a case of a large bladder stone with secondary right-sided hydronephrosis in a 3-year-old child who underwent exstrophy repair at the age of 7 months. During the exstrophy repair a no. 1 braided, polyester, nonabsorbable suture was used to close the pubic bones and served as a nidus for intravesical stone formation. This case substantiates the lithogenic nature of non-absorbable sutures in contact with urine as well as the need for close post-operative follow-up in these patients.