History and Objectives: Due to importance of hospital urinary infection and its complications and its prevalence and their different pattern of antibiotic resistance, the present study is carried out on patients admitted to the Shaheed Beheshti hospital in 1997.

Materials and Methods: A descriptive study was performed on 250 patients by random sampling who have been hospitalized for more than 72 hours, their microbiological culture test was negative at the time of admission. Microbiological urinary test was performed on each patient every 72 hour until the time of departure. Microbial classification and antibiotic resistance pattern were determined. Prevalence of bacteriuria with the probability of 95% was analyzed.

Results: Once patients are admitted to hospital, 16% (40 patients) acquired bacteriuria. Minimum and maximum rate of bacteriuria was 11 to 20 percent. Prevalence of infection was 3 times higher among females than males. 75% of patients having acquired the infection were older than 55 years. E.coli was the most common cause of infection and highest rate of resistance to co-trimoxazole and carbenicillin were shown.

Conclusion: Due to 11 to 20 percent rate of infection, an analytical study is needed to determine the major factors giving rise to hospital urinary tract infection and subsequent administrative policies to reduce such hospital induced infections. Training programs for hospital staff is also recommended.