PURPOSE: Metachronous bilateral UUTTs are rare. The authors reported baseline and long-term followup data for all patients diagnosed in Western Sweden during a 28-year period. MATERIALS AND METHODS: We performed a clinical and histopathological analysis of all patients in Western Sweden surgically treated for ureteral and renal pelvic tumors from 1971 to 1998. RESULTS: Of 768 patients a contralateral UUTT developed in 24 (3.1%) after a median of 46 months (range 2 to 232). The projected incidence after initial UUTT diagnosis was 2.7%, 5.8% and 6.5% at 5, 10 and 15 years, respectively. Median age of the 24 patients at initial UUTT diagnosis was 67 years and the median age at death was 77 years. Bladder cancer was significantly more common among patients with bilateral UUTT compared to those with unilateral UUTT (83% vs 31%, p