Objective To test the effect on urinary tract infections (UTIs) in patients needing continuous indwelling catheterization, of a newly designed urine-collecting system containing an antibacterial device which slowly releases silver ions onto the inner surface of the system. Patients and methods The study comprised a prospective controlled randomized trial; 213 patients ful®lled the inclusion criteria. They were randomized to a urine drainage system (comprising a Unometer 400 metering system or PP 2000N closed urine-bag system, both from Maersk Medical, Denmark) either with or without the antibacterial device. The ef®cacy was assessed as the number of UTIs and the time to infection in the 170 patients eligible for analysis. Results There were fewer UTIs in those using the system containing the antibacterial device (19% vs 24%), but the difference was not statistically signi®cant (P<0.05). Conclusion The potential importance of different infection routes were highlighted, suggesting that modi®cations to Foley catheters and urine-collecting systems attempting to prevent UTIs should focus not only on the intraluminal pathway, but on the internal and external pathways of infection.