We have examined composition of uroliths (qualitative and quantitative x-ray tests) and measured 24-h excretion of electrolytes (Cl-, NO2-, NO3-, SO4(2-), PO4(3-), cytrate, isocytrate and uric acid) using ion-exchange chromatography with a conductometric detector. We revealed correlations between ion characteristics, their concentration in the urine before and after treatment and composition of disintegrated uroliths and clinical data. This allowed us to identify some urinary ions which indicate activity of urolithogenesis, predisposition to urolithiasis, production of certain uroliths, reflect some processes running in patients with urolithiasis. We give concentrations of some urinary ions which can be considered normal and deviations which may indicate urolithogenesis.