This chapter discusses about the ureteroureterostomy, UU and ureteropyelostomy, UP technique in kidney implantation, where both approaches are carried out in ureteral strictures or urinary leaks, and preferably in an ipsilateral fashion. UU is an option for lower or mid ureter disease, whereas UP is an option for any level of disease. Prior to starting the procedure, some surgeons perform a cystoscopy with placement of a stent in the native ureter to ensure patency and easier intraoperative access of the native ureter. Once the native ureter has been mobilized proximally enough, it is transected and its end toward the native nonfunctioning kidney tied. The transplant kidney can be mobilized if Left donor kidneys transplanted to the right iliac fossa and right kidneys transplanted to the left iliac fossa have their pelvises exposed medially and require minimal mobilization. Once the site of the anastomosis has been identified and exposed, the native ureter is brought next to the transplant ureter or pelvis.