Urinary tract infections (UTIs) are among the most frequent infections in clinical practice worldwide. Their frequency and burden must be higher than available data suggest because they are not among mandatory diseases to be notified. Although there are many different proposals for classifying UTIs, classifications based on acquisition settings and complication status are more widely used. These include community- acquired UTIs (CAUTIs) or healthcare-associated UTIs (HAUTIs) and uncomplicated or complicated UTIs. As the most frequently seen infectious disease, CAUTIs affect more than 150 million people annually. Complicated UTIs in particular constitute a huge burden on healthcare systems as a frequent reason for hospitalization. The prevalence of HAUTIs ranges between 1.4% and 5.1%, and the majority of them are catheter-related UTIs. Community-onset HAUTIs have gained importance in recent years. As frequent infectious diseases, UTIs create clinical and economic burdens on healthcare systems, and they also affect quality of life determinants.