This paper describes our method for producing a rat model with an isolated bladder in situ in which the bladder makes no contact with urine. First, the right kidney was removed, then an external catheter was placed in the right ureter for bladder infusions, and next the left ureter was anatomosed to the proximal part of the descending colon. The animals were treated with antibiotics, and saline was infused daily into the bladder in order to prevent atrophy. This in situ model is considered to be useful in studies investigating the influence of specific compounds, such as carcinogens, on the bladder and its urothelium.