The characteristics of urinary tract infections (UTI), secretory IgA and urine composition of 24 patients (intestine group) who underwent operations using intestinal segments in urinary tract were compared with those of 26 complicated UTI patients without surgical intervention (control group). No significant differences were found in the frequency of either mono or polymicrobial infections between both groups. However, the frequency of bacterial isolation was different in the two groups, Streptococcus spp. and Providencia spp. were frequently isolated and P. aeruginosa was rarely isolated from the urine of the intestine group compared with from the urine of the control group. Furthermore, in polymicrobial infections of the intestine group with indwelling catheters, E. faecalis and Providencia spp. were frequently isolated simultaneously. The mean value of urinary secretory IgA was 94.0 micrograms/dl in the intestine group and 25.0 mu/dl in the control group (p less than 0.0001). The mean urinary osmolarity was 370 mOsm/kg in the intestine group and 500 mOsm/kg in the control group (p less than 0.005). The other parameters, including urinary pH and urea N concentration, showed no statistically significant differences. These findings suggest that urinary tract constructed from intestinal segments differs from the urinary tract without surgical intervention in the feature of UTI and anti-bacterial defense mechanisms.