What is a Foley Catheter/ Foley Balloon Catheter A Foley catheter is a thin, flexible and sterile tube which is passed through the urethra into the urinary bladder. Urine drains from the bladder into a bag which is attached to one of the lumens of the catheter. The urinary catheter is held in its place with a balloon at one end which is filled with sterile water. When is a Foley Catheter used? The need for catheterization arises in a number of conditions including: When there is hesitation or inability to urinate due to retention (due to anomalies in the urinary stream) When there is an anatomical obstruction to the urethra (prostate cancer etc.) To monitor urine samples of critical patient Material composition: latex rubber, silicone and silicone coated variants are available. Traditionally, these urinary catheters have been made from latex, however, silicone due to its more inert nature is now gaining preference especially for long term use and where cost is not a constraint.