Urinary tract infection (UTI) is a common and important clinical problem in all age groups. Diagnosis of UTI without localization is not difficult, while the differential diagnosis of UTI is complicated by the lack of specific criteria for pyelonephritis and cystitis. The presence of certain clinical symptoms in combination with a positive bacteriological examination of urine does not allow us to reliably determine the localization of the inflammatory process in the urinary system, which is important due to the different approaches to the treatment of pyelonephritis and cystitis. The review considers in detail the data of studies demonstrating insufficient sensitivity and specificity of the accepted markers of urinary tract infection. Studies have found that ESR and CRP cannot act as specific markers for UTI, especially in children with fever. It has been shown that the procalcitonin test can be considered as such a marker, however, a limited number of studies and a noticeable heterogeneity between studies do not allow us to state this fact definitely. In this regard, it is necessary to search for modern, more accurate biomarkers, that allow differentiating pyelonephritis and cystitis at the earliest stages. The article presents data of modern studies, demonstrating the role of cytokines as biomarkers of UTI, showing their role in differentiating UTI of the lower and upper parts. In addition, the potential role of antimicrobial peptides as diagnostic markers of UTI is considered.