A patient with renal extravasation due to ureteral calculus is described. A 58-year-old male visited our hospital with pain in the right lower abdomen, and showed peripelvic extravasation of the contrast medium by DIP aod CT. Extravasation was absent in DIP and the symptoms were alleviated 2 days after admission. The patient was discharged after 5 days. Peripelvic extravasation must be clearly differentiated from spontaneous rupture of the kidney.Peripelvic extravasation is a relatively uncommon condition, which is considered to be caused by renopelvic reflux due to obstruction of the urinary tract or compression of the ureter.This report describcs a patient with peripelvic urinary extravasation due to ureteral calculus.Around noon on August 26, 1987, a 58-year-old male noted pain of the right lower abdomen and right back, which disappeared spontaneously after about 2 hours. The patient presented with pollakiuria the next morning, and later developed oliguria while occasionally showing hematuria.As pain occurred at the same sites about 9 p. m. the same day and deteriorated, the patient visited our hospital.There was no relevant clinical history. On admission, the patient had a medium body build and showed a good nutritional condition, body temperature of 36. 5°C, blood pressure of 130/70 mmHg, and regular heart rate of 65/min. Slight tenderness was noted in the right lower abdomen and right back, but no external trauma was observed.The laboratory data on admission included : RBC 489 x 104, WBC 9, 200, Hb 14. 9 g/dl,GOT 28 IU/1, GPT 16 IU/1, LDH 475 IU/l, Na 133 mEq/1, K 3. 6 mEq/1, Cl 101 mEq/1, BUN 12 mg/dl, Cr 1. 4 mg/dl, and blood glucose 160 mg/dl. The results of urinalysis were :protein ( -), glucose ( +) , urobilinogen ( ) , and occult blood ( +).DIP was performed, suspecting ureteral calculus, and the contrast medium was found to