The two most common indications for long-term catheterization are recalcitrant urinary incontinence and urinary obstruction that is not corrected by surgery. For incontinent patients, if behavioral changes, nursing care, special clothes, special bed clothes, and medications have not been successful, then a device to collect urine must be considered. For men such a device is a condom catheter; for women an analogous external collection device would be very useful. Suprapubic catheterization may offer an alternative but has been inadequately studied in this patient population. Long-term urinary catheterization has salutary effects for selected patients including patient comfort, family satisfaction, and nursing efficiency and effectiveness. To the patient for whom any physical movement is uncomfortable or painful, and indwelling catheter may be preferable to frequent changes of clothes. Similarly, the family of of severely impaired patients may want to accept the risks of urethral catheterization in order to keep the patient dry. Further, to the extent that the indwelling catheter is effective in decubitus ulcer prevention and/or management, long-term catheterization may diminish the risk of bacteremia or death from soft tissue infection. These benefits of long-term urethral catheterization, in addition to its risks, should be examined in future studies. Once a urethral catheter is in place, even with good catheter hygiene, bacterial entry can be postponed only temporarily; eventually all patients become bacteriuric. Indeed, as the catheter remains in place, organisms continue to enter, others leave or die, and the bacteriuria becomes complex, polymicrobial, and dynamic. Some organisms, particularly recognized uropathogens such as E. coli and K. pneumoniae, appear to reside in the urinary tract itself. Others, such as P. mirabilis, P. stuartii, and M. morganii, probably establish a niche within the urinary catheter, thus increasing their ability to cause subsequent bladder bacteriuria. The complications of long-term urinary catheterization include fevers, acute pyelonephritis, and bacteremias (such as seen in short-term catheterized patients), as well as catheter obstructions, urinary stones, chronic renal inflammation, local periurinary infections, vasicoureteral reflux, renal failure, and, for very long-term catheterized patients, bladder cancer. The thrust of catheter care for the long-term catheterized patient is to prevent complications of the omnipresent bacteriuria. Unfortunately, clinical opportunities for preventing complications are limited.(ABSTRACT TRUNCATED AT 400 WORDS)