A case of simultaneous bilateral renal pelvic tumors is reported. A 64-year-old man with the chief complaint of gross hematuria and left flank pain was admitted. Clinical investigations revealed a tumor in the right pelvis and ureter, and another tumor in the left renal pelvis. The right ureteral tumor had invaded the bladder. Right nephroureterectomy, total cystectomy, left partial pyelectomy and ureterocutaneostomy were performed. By pathological examination, right renal pelvic and ureteral tumors were non-papillary transitional cell carcinoma, grade 3, pT4, and the left renal pelvic tumor was papillary transitional cell carcinoma, grade 2, pT1. To our knowledge, this is the 16th case of simultaneous bilateral urothelial tumors of the upper urinary tract in Japan.