Chronic kidney disease is an irreversible kidney damage caused by structural or functional renal impairment and persisting for more than 3 months. It is usually accompanied by albuminuria, proteinuria, abnormal histopathological and imaging findings as well as a drop in glomerular filtration rate below 60 mL/min/1.73 m². Due to the increasing number of patients, chronic kidney disease is referred to as “the epidemic of the 21^st century.” Early diagnosis allows for effective therapeutic intervention, which makes it possible to inhibit pathological processes and prevent disease in the future. Diagnostic difficulties in detecting early stages of chronic kidney disease are due to their asymptomatic nature and the fact that the markers widely used for renal function assessment are not very sensitive. Therefore, new, early, sensitive and specific markers of renal damage, whose introduction in everyday clinical practice would give a chance of a diagnosis at the very onset of the disease, before irreversible changes occur, are currently being sought. Although the results of scientific research are ambiguous, some of the candidate protein markers seem very promising. These include uromodulin, KIM-1, NGAL-1, NAG, FGF23, RBP4 and suPAR. The aim of the paper was to present a review of the latest research on the use of novel protein markers in the diagnosis of chronic kidney disease in paediatric and internal medicine patients.