Urinary tract infections belong to the most common types of infections. They are of great importance for the pathogenesis of urolithiasis. This dissertation analyses urinary tract infections in urolithiasis patients. For this purpose, the data of 1,544 patients who were hospitalized in the Urological Clinic of the Martin Luther University in Halle-Wittenberg between 1988 and 1992, as well as in 1996, were used to evaluate the frequency of urinary tract infections in these patients, the pathogen spectrum, and the antibiotic sensitivity of those pathogens. The comparison of the study periods from 1988 to 1992 and the year 1996 showed obvious differences in the pathogen spectrum and an increasing resistance towards antimicrobial agents. Community and hospital acquired UTI were considered separately. As an result, recommendations for a calculated antibiotic therapy to be used in the above mentioned urological clinic were given.