The material of this case was 1-year-old male cat with complaints of loss of appetite, stagnation, vomiting, paresis in the back extremities, reduction of urine output and icterus which admitted to the Animal Hospital of Faculty of Veterinary Medicine of Selcuk University. Perirenal pseudocyst, hepatic lipidosis and sepsis were determined by clinical, laboratory, histopathological and ultrasonographic examinations. Physical findings revealed hypothermia (35.8 Cº), leukopenia (4.23 m / mm3), tachypnea and bradycardia (64 beats/ min). Perirenal pseudocyst which determined by ultrasound examination was confirmed by necropsy. 0.9% NaCl and 5% dextrose solution, vitamin and amino acid, ceftriaxone 25 mg / kg, furosemide 1 mg / kg, n-acetylcysteine 70 mg / kg, ursodeoxycholic acid 15 mg / kg, dobutamine 1.25 andg / kg / min were used for protecting kidney function and for sepsis and hepatic lipidosis. Despite one week of treatment, the patient did not recover and died. In this case report, clinical, laboratory, ultrasonographic and necropsy findings of the iranian cat with sepsis associated with perirenal pseudocyst are presented. In conclusion, it was concluded that perirenal pseudocystic is genetically predisposed to persian cats and ultrasonographic examination is an important diagnostic method in the diagnosis of perirenal pseudocyst.