Urinary tract infection (UTI) can lead to kidney damage. The analysis of urinary enzyme activities is a sensitive, non-invasive method to recognise renal tubular lesions. The most important enzymes for kidney diagnosis, pathomechanism of urinary enzyme activity changes in the course of UTI and other factors influencing enzyme excretion are described. Interpretation of enzymuria, its clinical significance for kidney damage diagnosis and prognosis of disease are presented.