BACKGROUND: Nosocomial urinary tract infection (UTI) is the most frequent nosocomial infection and could be prevented through the intensive nosocomial infection control (NIC) or restricting the use of indwelling urinary catheter. The efficiency of the intensive NIC to prevent UTI for the patients with indwelling urinary catheter was investigated. METHODS: Study population consisted of 296 patients with indwelling urinary catheter in the intensive care unit (lCU) who didn't have UTI on admission. The incidence rates of nosocomial UTI were compared between 146 patients being provided with ordinary NIC from March 15 to July 31, 1995 (control group) and 150 patients being provided with intensive NIC from January 16 to October 31, 1996 (NIC group). RESULTS: There was significant decrease in the incidence of nosocomial UTI in the NIC group (35 UTI among 150 patients, 23.8%) than in me control group (68 UTI among 146 patients, 46.6%) (P<0.01). But there were no differences in age distribution, sex, admission route to the ICU and underlying diagnoses between two groups. Interval between insertion of urinary catheter and development of UTI was significantly prolonged in the NIC group (10.0 +/- 3.5 days) than in the control group(7.6 +/- 3.9 days) (p < 0.01) despite there were no differences in the duration of urinary catheterization in two groups. The most common organism isolated from the urine of the patients was Candida tropicalis in both groups and the other organisms were in the order of Enterococcus faecium, Pseudomonas putida, Staphylococcus epidermidis in the control group and in the order of Staphylococcus aureus, Acinetobacter baumannii, Enterococcus faecalis in the NIC group. Four of five Staphylococcus aureus isolated in NIC group were MRSA. CONCLUSION: This study result confirms the efficiency of intensive NIC fur decrease in the incidence of nosocomial UTI in patients with indwelling urinary catheter. But the incidence of nosocomial UTI should be decreased further through the continuous emphasis on NIC and it seems to be necessary to study the effect of each component of NIC with proper control of the risk factors for the development of nosocomial UTI in the future.