In urologic surgery, intestinal segments are used for bladder augmentation and replacement, substitution for ureter and genital reconstruction. Modern reconstructive techniques are widely used in young population as much as elderly population. The more widely these techniques are used, the more frequent the complications occur. The reasons and the treatment of these complications should be known. These complications are electrolyte disorders, sensory disorders, hepatic dysfunction, abnormal drug metabolism, stone formation, nutrition disorders, growth impairment, osteomalasia and rickets, infection and cancer. Most of these complications are associated with the amount of solutes absorbed throughout the intestinal segment. Factors affecting the absorption of solutes are the intestinal segment used, surface area, duration of urine exposure to intestinal segment, concentration of solutes, renal functions and intestinal osmolarity and pH.