The study has evaluated the effect of combined treatment including slightly mineralized hydrocarbonate-magnesium-calcium mineral water "Naftusya" of Zbruchansk field on the urinary system of 47 adult patients with urolithiasis and chronic pyelonephritis aged 24 to 76 years and 3 children of different age groups. 14 patients dropped out of the study group after 1-3 days after the start of treatment due to the negative reaction of the gastrointestinal tract to the reception of water; thus, study group consisted of 36 patients. At baseline, kidney or ureteral stones were diagnosed in all patients. For adult patients, water was administered at a dose 200 ml 3 times a day, for children--50-150 ml 3 times a day, 30-40 minutes before meals for 7-20 days. Examination of patients was performed using laboratory, ultrasound and radiographic methods. It was revealed that against the background of complex treatment, discharge of small stones, their fragments and urinary sand have occurred 1-3 days earlier than with standard treatment. There was no effect on calcium and inorganic phosphate metabolism. The trend to uric acid crystalluria and reducing the pH of urine was revealed. Statistically significant reduction of leukocyturia and erythrocyturia was identified. 60% of patients had a disappearance of bacteriuria or reduction of the titer of bacteria. The results led to the conclusion of advisability of use of mineral water "Naftusya" of Zbruchansk field in the complex treatment of inflammatory processes in the urinary system and for stimulation of discharge of ureteral stones with sizes enabaling to presume their independent discharge.