Introduction. The available information referring to the feline urolithiasis pathogenesis does not fully reflect the nature of changes taking place in the body, because it does not take into account the existing liver-kidney interrelationship. A systemic approach to studying this problem enables development of the targeted diagnostic strategies, increase of the subsequent therapeutic efficacy, as well as reduction of the possible clinical harm of polypragmasia. The aim of this article is to study the interrelationship between the nature of the hepatorenal system morphofunctional disorders and the level of metabolic processes in cats sick with struvite urolithiasis with the signs of cystolithiasis.Materials and Methods. The objects of the research were cats: the 1st experimental group consisted of the outbred female cats with tripelphosphate urolithiasis with signs of cystolithiasis, the 2nd experimental group — outbred castrated male cats with tripelphosphate urolithiasis with signs of cystolithiasis, the control group was mixed of the clinically healthy male and female animals. During the research, the results of the sick animals' clinical study, morphological and biochemical blood serum tests, hepatorenal system transabdominal ultrasonography were used, the urine macroscopic and biochemical examinations as well as urine sediment microscopy were carried out.Results. Against the background of hyperazotemia in sick animals (UREA — 14.70±1.30 mmol/L and 17.05±1.60 mmol/L; CREA — 173.90±6.06 μmol/L and 182.30±7.54 μmol/L; URIC ACID — 69.30±4.50 μmol/L and 73.48±4.83 μmol/L) and water-electrolyte metabolism disorder (Ca+2 — 2.89±0.05 mmol/L and 3.04±0.12 mmol/L; P+3 — 3.12±0.06 mmol/L and 3.20±0.09 mmol/L; iCa+2 — 1.39±0.03 mmol/L and 1.42±0.02 mmol/L; Cl- — 125.58±1.19 mmol/L and 129.90±1.06 mmol/L) there were observed: a disorder in the hepatobiliary system functioning due to elevation of the main hepatic transaminase activity (AST — 41.74±5.35 unit/L and 49.30±6.74 unit/L; ALT — 85.82±6.15 unit/L and 90.05±6.50 unit/L; ALКP — 45.61±3.10 unit/L and 48.16±2.86 unit/L; AAR — 0.49±0.03 and 0.54±0.02), elevation of total bilirubin level (BILT — 5,76±0,15 μmol/L and 6,08±0,24 μmol/L) and bilirubin direct (BILD — 1,40±0,03 μmol/L and 1,62±0,02 μmol/L), as well as elevation of the gamma-glutamyl transpeptidase (GGT — 6,67±1,01 unit/L and 7,90±0,90 unit/L) and lactate dehydrogenase (LDH — 215,47±10,30 unit/L and 219,04±9,27 unit/L) activity level. The acoustic shadowing of the hepatorenal system organs confirmed the signs of acute hepatitis against the background of cystolithiasis due to the existing anatomical relationship between kidneys and liver.Discussion and Conclusion. The results of the sick animals’ blood serum examination indicated the progression of the hematopoietic dysfunction during the tripelphosphate urolithiasis, which contributed to the development of the circulatory tissue hypoxia in the liver-kidney system. The development of the hyperazotemia contributed to the elevation of the main hepatic transaminase activity and building-up of the functional disorders in the hepato-biliary system of sick cats in response to the acute inflammatory process going on in the urogenital tract. The carbohydrate and lipid metabolism disorders indicated the liver metabolic activity disorder and its parenchymal damage on the background of urolithiasis. The electrolyte and water metabolism disorders, the development of the hyperproteinemia in test cats with the tripelphosphate urolithiasis contributed to the damage of the hepatorenal system organs due to development of the compensated metabolic acidosis and hyperchloremia.