PURPOSE: To investigate the incidences of newly diagnosed arsenic-related bladder cancer (BC), upper urinary tract UC (UTUC), and renal cell carcinoma (RCC) in Taiwan. METHODS: Cancer data for 1979-2019 were extracted from the Taiwan Cancer Registry Database. According to birth residency, individuals were divided into Z0, Z1, Z2, and Z3 areas according to the groundwater As levels in the 1970s and whether BFD was endemic to an area. New diagnosis rates were analyzed. The investigation period was divided into early (1979-1999) and late (2000-2019) periods to compare the changes after the As-contaminated water use stopped. RESULTS: 26,908, 59,838, and 34,245 newly diagnosed cases of RCC, BC, and UTUC, respectively, were identified. Age-standardized incidence showed the RCC and BC patients were predominantly male. As contamination was not correlated with RCC incidence. Regarding BC and UTUC in Z3, higher As groundwater levels accompanied with higher incidence rates in both sexes. When comparing late to early period, reverse change with decreased incidence was noted in BC and UTUC in Z3 populations. (BC male: mean ± SD: 45.1 ± 10.8 vs 69.7 ± 10.4, ∗∗∗P <
0.0001, female: mean ± SD: 32.2 ± 8.9 vs 50.4 ± 13.4, ∗∗P <
0.007
UTUC male: mean ± SD: 35.73 ± 8 vs 46 ± 13.4, ∗∗P <
0.007
female: mean ± SD: 30.7 ± 7.2 vs 38.5 ± 6,2, ∗∗P <
0.007). CONCLUSION: Exposure of arsenic is related to incidence of BC and UTUC but RCC in Taiwan. After stopping drinking As-containing groundwater since 1980s, significant decrease in BC and UTUC incidence was also noted.