In the examination of a 52-year-old Caucasian woman with a 2-year history of right flank pain and lower urinary tract symptoms, a cystic mass was observed in her right kidney in ultrasonography. The cystic mass was diagnosed as a renal hydatic cyst in computed tomography. The patient was hospitalized with the diagnosis of renal hydatic cyst and no abnormality was found in laboratory and urine testing. No laboratory analysis was performed for a hydatic cyst; however, a renal hydatic cyst was diagnosed as a result of radiological findings. The patient’s history revealed no close relationship with animals. It was learned that the patient received medical treatment because of cerebrovascular disease and that she had no neurologic deficit for the time being. She had only taken medical treatment due to collagen tissue illness for 15 years. Subsequently, she was accepted to our clinic for surgery and open complex cyst removal was done under general anesthesia. The kidney was sutured watertight. However, in the postoperative period, a ureteral double j stent was placed because the drainage did not stop in the following 3-week duration. Because drainage of 250cc daily continued without any decrease the week following the double j stent placement, intravenous pyelography (IVP) was applied and urinary leakage was found. Urinary drainage was more prominent at night than during the day (250 versus 50cc). Subsequently, oral desmopressin was started at a dosage of 0.2mg/day in order to decrease the nocturnal urinary drainage; no abnormal situation was observed in serum electrolytes (specifically hyponatremia). The patient’s drainage decreased dramatically to a daily total of 50cc and she was discharged on the fifth day of the medical treatment after the drainage had stopped. After 1 week when the patient came for follow-up, the desmopressin treatment was ended. IVP was applied 3 weeks after the patient was discharged, and a urogram showed that the two kidneys were active and the double j stent was removed because no urinary leakage was observed.