A six-year-old castrated american shorthair cat was brought to us with the main complaint of hydronephrosis of the left kidney. Radiography and ultrasonography revealed dilatation of the left renal pelvis and proximal ureter, and the presence of a urolith in the right renal pelvis. Suspecting obstruction of the left ureter, we performed intravenous urography, but the contrast images were unclear. Therefore, antegrade pyelography from the left kidney was performed. This showed partial obstruction of the left ureter by uroliths, and identified the sites of these uroliths. The uroliths were successfully removed by ureterotomy, and the cat has been in good condition without any urinary problems for one year after surgery. From this, antegrade pyelography was thought to be effective in diagnosing ureterolithiasis and localization of uteliths.