When an ileal loop is used to replace the ureter or to create a urinary pouch, an adequate anti-reflux mechanism is essential. Intussusception of the ileal wall can be used but a proper technique must be chosen to prevent necrosis of the nipple. Good knowledge of the vascularization of the ileal wall is necessary. Leaving a 1-cm strip of mesenterium when stripping it from the ileal wall provides adequate circulation. Nipples of 3 cm or longer are enough to create an anti-reflux mechanism.