Clinicopathological parameters and therapeutic results of 100 patients with primary pyeloureteral cancers were examined, and prognostic factors were identified by monovariable and multivariable analyses. For the whole group, the 5- and 10-year survival rates were 57.0% and 44.8%, respectively. The site-specific 5-year survival rates were 61.0% for pelvic cancer, 51.9% for ureteral cancer, and 61.7% for pyeloureteral cancer, showing no significant differences among the sites. Monovariable analysis indicated age, tumor form, and histological stage and grade as important prognostic factors. Using multivariable analysis, concurrence of bladder cancer, age, histological stage, radiotherapy, surgery, chemotherapy, and histological grade were shown to be prognostic factors, given in order of decreasing importance. Age and histological stage, which were common to the results of both analyses, were considered to be most important as prognostic factors.