OBJECTIVES: To determine changes in the population-based incidence rates, degree of histologic verification, and morphologic distribution of tumors of the kidney, pelvis, and ureter and bladder in both sexes for the duration of 60 years in Denmark. METHODS: Age-standardized incidence rates in 5-year age and calendar intervals, histologic verification and morphologic distribution were derived from reports to the Danish Cancer Registry. RESULTS: The incidence of kidney tumors increased by 78% among men and 32% among women during the study period; the incidence of pelvis and ureter tumors increased by 1070% and 2785%, respectively, and those of bladder tumors increased by 325% and 195%, respectively. The incidence of Wilms tumor was stable; the incidence of other kidney tumors leveled out during the last 30 years of the period and those of other 2 groups during the last 20 years. The frequency of histologic verification was stable for pelvis and ureter cancers and Wilms tumor and increased for kidney and bladder tumors. Most of the kidney tumors were of epithelial origin and most others were of urothelial origin. CONCLUSIONS: The overall incidences of all tumors increased in both sexes during the 60-year period. Some of the increase could be due to improved diagnosis. The recent decline in rates might be due to reduced exposure to risk factors.