A case of bilateral asynchronous ureteral tumors in a 58-year-old man associated with a horseshoe kidney was reported. First, left heminephrectomy with total left ureterectomy had been performed because of the left ureteral carcinoma. Three years and 8 months later, he was admitted and an emergency right nephrostomy was made on account of false anuria. Then, right ureterectomy with total cystectomy was the choice of treatment against the ureteral tumor on the right side. This case of bilateral ureteral tumors associated with a horseshoe kidney appears to be the first one reported in the Japanese literature.