In order to demonstrate the role of saliva with high concentration of urea and alkalinity, preventing dental caries in the uremic patients, 4 groups of children were studied: I healthy controls, II children with successful renal transplantation, III uremic children in dialysis and IV uremic children with conservative treatment. The results show a direct correlation between increase of saliva urea concentrations and decrease in saliva hydrogen ion concentration. Higher values of urea and more alkaline pH were found in children with uremia, with or without dialysis. Despite that there was not a statistically significant difference in the caries-lost-obturation index: 0.252 was found in the group of healthy controls and the lowest was 0.119, in the patients with uremia and dialysis. The results suggest that a protector role of saliva in uremic children is possible.