Urinary tract catheters are hollow and flexible tubes used to facilitate urine output or to achieve urine transit through them. We can find different types of catheters depending on the purpose they have been designed for: urethral, cystostomy and ureteral catheters among others. We review the indications for insertion of these catheters, their designs, composition, covering materials, insertion techniques and associated complications. Pediatric catheters are behind what is produced for adults, so we perform a bibliographic review about urinary catheters in general with emphasis on the pediatric patient.