['To elucidate the importance of bacteriuria in patients with a continent urinary diversion.', 'Eighteen asymptomatic patients (16 women and two men, with a mean age of 53 years [range 22-73]) with ileal reservoirs coupled to the skin for urinary diversion were studied. Consecutive urine cultures were performed over 5 months. Concomitant measurements of antibody titres against Escherichia coli and Proteus, and C-reactive protein (CRP) values were made.', 'The results of the urine cultures varied considerably between samples. Increased titres of antibodies against E. coli were seen in several patients but the correlation with bacteriuria caused by E. coli was weak (sensitivity 33%, specificity 56%). Increased titres of antibodies against Proteus were rarely seen and in no patient correlated with bacteriuria caused by Proteus. Increased levels of CRP were seen in three patients.'] Does bacteriuria in patients with a continent ileal reservoir for urinary diversion regularly require antibiotic treatment?