Transurethral incision (TUI) was performed as the initial treatment in 10 children with ureteroceles. Three patients had ureteroceles associated with a single ureter. TUI relieved hydronephrosis and preserved renal function in all 3 cases. Urinary tract infection developed in no patients. However, all the patients required an antireflux operation because of postoperative vesicoureteral reflux (VUR). Seven children had a total of 8 ureteroceles associated with a duplex system. TUI resulted in preservation of the upper pole function in 6 of the 8 ureteroceles. Urinary tract infections and VUR developed in 3 and 7 patients, respectively. Common sheath reimplantation was performed in 2 ureteroceles. TUI relieves obstruction before the onset of devastating infections although it carries the risk of postoperative VUR. We recommend TUI as the initial treatment for ureteroceles associated with both single and duplex systems.